OPHIR BeamSquared User manual

BeamSquared®
User Guide
Beam Propagation Analyzer
For Windows 7®
and Window 10®64 BIT
For Sales, Service or Technical Support
Phone: [phone]
Fax: [phone]
Service Email
[e-mail]
Sales Email
[e-mail]
Ophir-Spiricon, LLC
3050 North 300 West
North Logan, Utah 84341
©2019 Ophir-Spiricon, LLC

Dear Ophir-Spiricon Customer,
Thank you for your recent purchase of the BeamSquared system.
At Ophir-Spiricon we strive to provide the highest level of leading edge photonic measurement technology and
service possible. We hope that your experience with us is a pleasant one, and anticipate the relationship we
build will serve your photonic measurement needs for years to come.
As a valued customer, your comments and opinions are always very important to us. If you have any
concerns, questions, or comments, bring them to our service department’s attention. We are ready to help
with everything from basic setup to working with you to find solutions for your most complex photonics
measurement needs.
Thank you once again for your business and please let us know if we can be of assistance.
Sincerely,
Ophir-Spiricon, LLC
Ophir-Spiricon, LLC
3050 North 300 West
North Logan, UT 84341, USA
Tel [phone]
Fax [phone]
www.ophiropt.com/photonics

How to Use this Guide
It is recommended that users review this guide before setting up and using the BeamSquared system. This
guide will assist users in becoming familiar with the M2measurement theory as well as acquire a basic
understanding of the BeamSquared operation. Furthermore, familiarity with this guide will aid the user with
system alignment and interpretation of M2results.
BeamSquared Measurements are based on beam propagation theory and employ ISO measurement standards.
Users who are unfamiliar with beam propagation theory or those who wish to have a refresher on
these concepts please review Chapters 5 and 6.
Chapter 1 General Information –Contains safety warnings, technical information, and specifications for
hardware and software.
Chapter 2 Setup –Contains information on how to setup the BeamSquared hardware and software.
Chapter 3 Operating Controls and User Interface –Describes the controls and displays within the
BeamSquared software. It is recommended to become familiar with these and their meaning before
attempting to operate the BeamSquared system.
Chapter 4 Operation –Details the operating modes and how to use the BeamSquared System.
Chapter 5 M2Theory and Tutorial –Presents a tutorial on M2theory, practical insights behind the
propagation measurements and the ISO measurement methods, and a description of the features in the
BeamSquared software.
Chapter 6 M2Computations –Contains computational information on how M2is calculated.
Chapter 7 Troubleshooting –Contains troubleshooting tips and how to respond to error messages.
Chapter 8 BeamSquared Automation Interface –Provides details of the BeamSquared Automation
Server properties, methods, and events.
Chapter 9 Manual M2Measurements –Presents set up instructions and details the manual mode
operation.
Appendix A Lens Calibration Adjustments –Contains lens wavelength correction information for Plano-
convex lenses.
Appendix B Warranty –Contains warranty information.
Appendix C BeamSquared Supported Cameras –Contains a list of cameras supported by BeamSquared
with links to the camera specifications.
Appendix D Camera Information –Contains camera-specific controls and features.
Symbol Notation
Indicates general information that poses no risk.
Indicates important information about the product with little or no risk.

Indicates warning information. Failure to follow instruction may result in harm to the user or product
damage.
Indicates that the instruction refers to operating BeamSquared in Manual Mode.

Table of Contents
How to Use this Guide.............................................................................................................................. 3
Table of Contents .................................................................................................................................... 5
Chapter 1 General Information ........................................................................................................... 11
Safety...................................................................................................................................... 111.1
BeamSquared Model Numbers ................................................................................................... 121.2
BeamSquared Manual Mode Models..................................................................................... 121.2.1
Automated BeamSquared Models ........................................................................................ 121.2.2
Specifications ........................................................................................................................... 131.3
BeamSquared Optical Train Dimensions...................................................................................... 151.4
Software Information................................................................................................................ 161.5
Chapter 2 Setup................................................................................................................................ 17
Equipment ............................................................................................................................... 172.1
BeamSquared Software Installation............................................................................................ 172.2
Prepare the BeamSquared for Operation..................................................................................... 182.3
Mount the Optical Train ...................................................................................................... 182.3.1
Install the Camera.............................................................................................................. 192.3.2
Connect BeamSquared ....................................................................................................... 202.3.3
External Attenuation of the Beam............................................................................................... 21
2.4
Attenuation ....................................................................................................................... 222.4.1
Beams < 1 Watt ............................................................................................................. 222.4.1.1
Beams < 400 Watts ........................................................................................................ 222.4.1.2
Beams < 2000 Watts ...................................................................................................... 222.4.1.3
Beams > 2000 Watts ...................................................................................................... 222.4.1.4
Beam Alignment and Setup for Auto Mode.................................................................................. 222.5
Distance from Laser ........................................................................................................... 232.5.1
Initial Setup and Rough Beam Alignment ............................................................................. 242.5.2
Live Playback.................................................................................................................. 242.5.2.1
External Steering Mirrors ................................................................................................. 242.5.2.2
Laser Mounting Height .................................................................................................... 242.5.2.3
Gunsight Alignment Tool ................................................................................................. 242.5.2.4
Precision Beam Alignment................................................................................................... 262.5.3
Ghost Beams.................................................................................................................. 272.5.3.1

Beam Axial Alignment......................................................................................................... 282.5.4
Step Size and Start/Stop Selection ............................................................................................. 292.6
Chapter 3 Operating Controls and User Interface ................................................................................. 30
User Interface .......................................................................................................................... 303.1
Title Bar ............................................................................................................................ 303.1.1
Ribbon Tab........................................................................................................................ 313.1.2
Ribbon Bar ........................................................................................................................ 313.1.3
Panels............................................................................................................................... 313.1.4
Display Area ...................................................................................................................... 313.1.5
Status Bar ......................................................................................................................... 313.1.6
Application Tools ...................................................................................................................... 323.2
File Access Window ............................................................................................................ 323.2.1
TIFF Image Format......................................................................................................... 333.2.1.1
Exporting TIFF Images for use with HDF5.................................................................... 333.2.1.1.1
Show/Hide Ribbon Bar........................................................................................................ 343.2.2
Ribbon Group Visibility........................................................................................................ 343.2.3
Run Ribbon.............................................................................................................................. 353.3
Live Playback..................................................................................................................... 353.3.1
Start ................................................................................................................................. 353.3.2
Configure .......................................................................................................................... 35
3.3.3
Info .................................................................................................................................. 353.3.4
Mode ................................................................................................................................ 363.3.5
Boundary Check................................................................................................................. 363.3.6
Real Time M2..................................................................................................................... 363.3.7
Load and Save................................................................................................................... 363.3.8
Abort Run.......................................................................................................................... 373.3.9
Finish Run ......................................................................................................................... 373.3.10
Table Ribbon............................................................................................................................ 373.4
Rail................................................................................................................................... 373.4.1
Attenuation ....................................................................................................................... 383.4.2
Table Info ......................................................................................................................... 383.4.3
Lens Info........................................................................................................................... 383.4.4
Source Ribbon.......................................................................................................................... 383.5
Data Source....................................................................................................................... 383.5.1

Exposure........................................................................................................................... 393.5.2
Gamma ............................................................................................................................. 393.5.3
Trigger.............................................................................................................................. 393.5.4
Trigger Pyrocam ................................................................................................................ 403.5.5
Camera Info ...................................................................................................................... 403.5.6
Data Ribbon............................................................................................................................. 403.6
Data Logging..................................................................................................................... 413.6.1
Report............................................................................................................................... 413.6.2
Views Ribbon ........................................................................................................................... 443.7
2D Beam Display................................................................................................................ 443.7.1
Measured Caustic Display ................................................................................................... 443.7.2
3D Beam Display................................................................................................................ 453.7.3
Run Steps.......................................................................................................................... 463.7.4
Results.............................................................................................................................. 473.7.5
Result Settings ............................................................................................................... 503.7.5.1
Positional Stability .............................................................................................................. 513.7.6
Interface Customization ............................................................................................................ 533.8
Docking Handles ................................................................................................................ 533.8.1
Chapter 4 Operation.......................................................................................................................... 54
Operating Modes ...................................................................................................................... 54
4.1
Automated Stepping........................................................................................................... 544.1.1
Automated ISO Setup......................................................................................................... 544.1.2
Four Cuts Method............................................................................................................... 554.1.3
When to use the Four-Cuts method.................................................................................. 564.1.3.1
Four-Cuts on Two Axes ................................................................................................... 564.1.3.2
Step Table......................................................................................................................... 574.1.4
Real Time M2Mode ............................................................................................................ 574.1.5
BeamSquared Operation ........................................................................................................... 584.2
Configuration Wizard.......................................................................................................... 584.2.1
Step by Step Wizard........................................................................................................... 624.2.2
Data Collection in Auto Mode..................................................................................................... 654.3
Useful Operations and Functions................................................................................................ 654.4
Z Locations........................................................................................................................ 654.4.1
Plotted Curve Fit ................................................................................................................ 654.4.2

Exclude Data Points............................................................................................................ 664.4.3
Interpreting Results............................................................................................................ 664.4.4
Divergence..................................................................................................................... 674.4.4.1
Chapter 5 M2Tutorial and Theory ....................................................................................................... 68
Introduction to M2.................................................................................................................... 685.1
M2< 1..................................................................................................................................... 685.2
Laser Beam Parameters ............................................................................................................ 695.3
An M2Tutorial .......................................................................................................................... 705.4
The Transforming Lens....................................................................................................... 715.4.1
Beam Width Measurement Criteria....................................................................................... 725.4.2
Spot Size and Resolution .................................................................................................... 735.4.3
Attenuation and Distortions................................................................................................. 765.4.4
M2Theory of Operation............................................................................................................. 765.5
Operation Limitations................................................................................................................ 775.6
Electro-Mechanical Operation..................................................................................................... 775.7
Data Collection ......................................................................................................................... 785.8
Chapter 6 M2Computations................................................................................................................ 79
Curve Fitting ............................................................................................................................ 796.1
M2, K Factor, and BPP......................................................................................................... 796.1.1
Translation Equations ......................................................................................................... 79
6.1.2
Full Divergence Angle...................................................................................................... 796.1.2.1
Waist Width ................................................................................................................... 806.1.2.2
Waist Location................................................................................................................ 816.1.2.3
Waist Location Relative to Principal Plane .................................................................... 816.1.2.3.1
Waist Location Relative to Laser Aperture .................................................................... 826.1.2.3.2
Rayleigh Range.................................................................................................................. 826.1.3
Astigmatism and Asymmetry ............................................................................................... 836.1.4
Focal Length Calculation ..................................................................................................... 836.1.5
Path Length Calibration Values ............................................................................................ 846.1.6
Z Lens ........................................................................................................................... 856.1.6.1
Z Fixture ........................................................................................................................ 856.1.6.2
Z Camera ....................................................................................................................... 856.1.6.3
BeamSquared Distance....................................................................................................... 866.1.7
Chapter 7 Troubleshooting................................................................................................................. 88

Setup and Startup Problems ...................................................................................................... 887.1
Operation Problems .................................................................................................................. 897.2
Chapter 8 BeamSquared Automation Interface .................................................................................... 91
Evolution of the Automation Interface ........................................................................................ 918.1
Recommended Skill Set............................................................................................................. 918.2
Documentation......................................................................................................................... 928.3
Examples ................................................................................................................................. 928.4
Chapter 9 Manual M2Measurements ................................................................................................... 93
Electro-Mechanical Operation..................................................................................................... 939.1
Spot Size Resolution ................................................................................................................. 939.2
Manual Mode ........................................................................................................................... 969.3
Optical Rail Setup............................................................................................................... 969.3.1
Beam Alignment and Setup for Manual Mode........................................................................ 979.3.2
Adjusting Beam Alignment .................................................................................................. 989.3.3
Step by Step Wizard........................................................................................................... 999.3.4
Exposure......................................................................................................................... 1019.3.5
Appendix A Lens Calibration Adjustments ............................................................................................ 102
A.1 Plano convex Lens Calibration.................................................................................................. 102
A.2 Refractive Index of Common Lens Materials.............................................................................. 103
Appendix B Warranty......................................................................................................................... 104
Appendix C BeamSquared Supported Cameras..................................................................................... 105
Appendix D Camera Information...................................................................................................... 106
D.1 SP300.................................................................................................................................... 106
Supplied Accessories ........................................................................................................ 106D.1.1
External Trigger Control.................................................................................................... 106D.1.2
GPI/O Connector Description............................................................................................. 106D.1.3
D.2 SP920.................................................................................................................................... 107
Supplied Accessories ........................................................................................................ 107D.2.1
External Trigger Control.................................................................................................... 107D.2.2
GPI/O Connector Description............................................................................................. 107D.2.3
D.3 XEVA XC-130.......................................................................................................................... 108
Camera Installation .......................................................................................................... 108D.3.1
Getting Started with Xeva XC-130 camera .......................................................................... 109D.3.2
XenICs XEVA XC-130 Camera Operation............................................................................. 110D.3.3

Chapter 1 General Information
Safety1.1
Optical Radiation Hazards
Use of this instrument requires the operator to work near the optical path of lasers. Exposure to
radiation from these lasers may be sufficient to warrant the use of protective equipment.
Unless the laser’s optical path is enclosed, the operator should protect against accidental exposure.
Exposure to personnel other than the operator must also be considered. Hazards include direct
beam exposure and reflected radiation.
When working with an unenclosed beam path, it is advisable to do so while the laser is powered
down or at reduced power levels. Whenever there is a risk for dangerous exposure, protective eye
shields and clothing should be worn.

BeamSquared Model Numbers1.2
All standard BeamSquared models are sold without a computer, or external optical accessories. An accessory
model of BeamSquared is available for purchase that allows operation with an existing SP300, SP920, or XC-
130 camera. Existing cameras must be returned to the factory to add the BeamSquared license.
BeamSquared Manual Mode Models1.2.1
The Manual Mode System requires the end user to provide a manually operated system (see Chapter 9). The
optical train must include a focusing element, a means to translate the camera behind the focusing element, a
laser beam attenuation system, and a way to block the beam from reaching the camera sensor during
calibration. Accurate results depend on a well-designed optical system. The user has full responsibility for the
system performance.
Part Number
Model Number
Description
SP90410
BSQ-PY-M
Pyrocam license for BeamSquared.
Automated BeamSquared Models1.2.2
Part Number
Model Number
Description
SP90443
BSQ-SP300
SP300 camera and license with BeamSquared hardware.
SP90502
BSQ-SP920
SP920 camera and license with BeamSquared hardware.
SP90444
BSQ-XC130
XC-130 camera and license with BeamSquared hardware.
SP90445
BSQ-A
BeamSquared hardware accessory model, sold without a
camera, for customers that already own a compatible
camera system.
SP90449
BSQ-Lens Kit 266-1550
266-440nm UV 500mm FL
430-700nm VIS 500mm FL
430-700nm VIS 400mm FL
650-1000nm NIR 400mm FL
1000-1550nm NIR extended 400mm FL*
SP90450
BSQ-Lens Kit 650-1700
650-1000nm NIR 400mm FL
1000-1700nm NIR extended 400mm FL
SP90451
BSQ-Lens UV 500mm
266-440nm UV 500mm FL
SP90452
BSQ-Lens VIS 500mm
430-700nm VIS 500mm FL
SP90453
BSQ-Lens VIS 400mm
430-700nm VIS 400mm FL
SP90454
BSQ-Lens NIR 400mm
650-1000nm NIR 400mm FL
SP90455
BSQ-Lens XNIR 400mm
1000-1550nm NIR extended 400mm FL
SP90485
BSQ-Lens XNIR 600mm
1000-1550nm NIR extended 600mm FL
* The SP300 and SP920 cameras are only sensitive between 190-1100nm.

Specifications1.3
Environmental
Storage Temperature
-30°C to 65°C
Storage Humidity
95% maximum (non-condensing)
Operating Temperature
10°C to 40°C
Operating Humidity
95% maximum (non-condensing)
Power Requirements*
Input Voltage
90 –264 V AC
AC Line Current
1.6 A
Line Frequency
47Hz to 63Hz
Output Voltage
24V DC @ 5 A
Output Power
120 W
* For the optical train only. The PC computer supplies the power for the system components and the SP300
and SP920 CCD camera. The XC-130 camera has a separate power supply.
Physical
Weight
26 lbs. (without camera)
Standard Optics
Different lenses are required for different wavelength regions, spot sizes, and divergences. Five lenses are
included with the SP300 and SP920 systems, and two lenses with the XC-130 system. See below for nominal
focal lengths. Additional lenses must be ordered separately.
BSQ-SP300
BSQ-XC130
BSQ-SP920
BSQ-A
Included
Lenses
266-440nm UV
500mm FL
430-700nm VIS
500mm FL
430-700nm VIS
400mm FL
650-1000nm NIR
400mm FL
1000-1550nm NIR
extended 400mm FL*
650-1000nm NIR
400mm FL
1000-1700nm NIR
extended 400mm FL
266-440nm UV
500mm FL
430-700nm VIS
500mm FL
430-700nm VIS
400mm FL
650-1000nm NIR
400mm FL
1000-1550nm NIR
extended 400mm FL*
266-440nm UV
500mm FL
430-700nm VIS
500mm FL
430-700nm VIS
400mm FL
650-1000nm NIR
400mm FL
1000-1550nm NIR
extended 400mm FL*
* The SP300 and SP920 cameras are only sensitive between 190-1100nm.

Attenuation
Attenuation Range
Nominally from ND 1.0 to ND 4.8. Actual values vary with wavelength.
Optical Limits
Wavelength Range
266-1700nm limited by camera.
The CCD camera is operational from 266 to 1100nm. InGaAs camera operates
from 900 to 1700nm.
Beam Size
BeamSquared Auto Mode 1mm –10mm.
BeamSquared Manual Mode 1mm –20mm.
Varies with wavelength, waist size, location, and M2. See section 5.4.3.
Damage Limits
CCD Camera*
.15 mW/cm2CW mode
1.0 μJ/cm2pulse mode
Both of the above for an M2=1 @ 1064nm
* WARNING! CCD cameras can be damaged by power in excess of .15 mW/cm
2or energy in excess
of 1 μJ/cm
2. BeamSquared employs a focusing optic. While it may be that the laser input power or
energy density measures well below this damage threshold, it can easily exceed these levels when
focused onto the camera sensor. Use caution and err on the side of safety. CCD cameras are costly
to repair or replace.
General
Accuracy
±5% typical
(Note: Accuracy can be degraded by a variety of situations, consult text.)
Measurement Cycle Time
< 1 minute typical, depending on setup conditions and operating mode.
CCD Camera Attachment
Standard C-mount, 90° camera on axis rotation
Translation System
Step motor-driven ball screw
Translation Stage Resolution
.05mm
Refer to the Pyrocam user guide or the Ophir-Spiricon website for camera specific specifications.
The following descriptions assume operations in Auto mode. Instructions that are specific to
operating in Manual mode are indicated by a symbol.

BeamSquared Optical Train Dimensions1.4

Software Information1.5
BeamSquared is designed to measure the propagation characteristics of UV, VIS, NIR, and extended NIR laser
beams. For questions related to BeamSquared or compatible accessories, contact Ophir-Spiricon’s service
department (servic[email protected].com).
Manual users can also measure THz laser beams in manual mode with a Pyrocam IV or IIIHR.
If you are using a camera that was purchased with a BeamGage system the camera should be
returned to the factory to determine if it is suitable for automated beam propagation measurements.
BeamSquared measures propagation characteristics in both the X and Y axes and displays the following
parameters:
Waist diameters
Full angle divergences
Waist locations
Rayleigh lengths
M2or K and BPP factor
Astigmatism
Asymmetry
BeamSquared employs Ultracal to achieve the highest possible measurement accuracy.
Automated BeamSquared Required Equipment:
A PC computer running Windows 7 or Windows 10
BeamSquared hardware
A SP300, SP920, or XC-130 camera
A laser beam attenuation device
Automated BeamSquared Optional accessories:
One pair of beam steering mirrors
Manual BeamSquared Required Equipment:
A PC computer running Windows 7 or Windows 10
A Pyrocam IV or IIIHR camera
A beam-focusing element with known focal length
A laser beam attenuation device
A beam block to shield the camera during calibration
An optical rail or other means of accurately positioning the camera with relationship to the
focusing element
PC Specifications
A personal computer running Windows 7 or Windows 10 64 bit operating system.
For best performance:
oGraphics card with 1GB dedicated memory or Intel Processor Graphics Core i3 or better
oAt least 8GB of main memory
oAt least 50GB of hard disk space available
oA high-resolution color monitor, 1920x1080 minimum recommended

Chapter 2 Setup
Equipment2.1
The following components are found in your BeamSquared system:
BeamSquared System Components
1. BeamSquared M2Measurement System
2. BeamSquared Lens Kit
3. T-handle 7/64” Hex Wrench
4. TTL Camera Trigger Cable
5. Optional Use Leveling Feet (4)
6. AC-DC 24V 5A Adapter
7. CCD Camera Certificates
8. Laser Profiling Grade CCD Camera
9. Base Clamps (4)
10. Software Installation DVD
11. USB-A 3.0 to USB-A 3.0 IP68 Cable
12. USB-A 3.0 to USB 3.0 Micro Cable
13. Gunsight Beam Alignment Tool
BeamSquared Software Installation2.2
There are two ways to install the software from the Ophir-Spiricon provided DVD. This procedure works as
described on Windows 7 and 10 operating systems. All installations must be performed with
Administrator privileges.
1. If the computer is setup to Auto Play DVDs do the following:
a. Insert the supplied DVD into the DVD drive and wait for the Ophir-Spiricon Software Auto
Install screen to appear.
b. Click on the Software Install button.
c. Follow the directions that appear on the screen.
2. If the computer does not have the Auto Play feature enabled:
a. Insert the supplied DVD into the DVD drive and open Windows Explorer.
b. Select My Computer and right-click the DVD drive that contains the Ophir-Spiricon disk. Click
on the Autoplay option. This will open the Ophir-Spiricon Software Auto Install screen.
c. Click on the Software Install button.
d. Follow the directions that appear on the screen.
The BeamSquared icon appears on the desktop after installation completes.
If your computer does not have a DVD drive, the software may be downloaded from our website
(https://www.ophiropt.com/laser--measurement/software-download?r=drp).

Prepare the BeamSquared for Operation2.3
This section covers installation for the BeamSquared hardware. For manual mode installation see
Chapter 9.
Mount the Optical Train2.3.1
1. The optical train can be mounted either vertically or
horizontally depending on the system needs.
2. Place the input aperture on the same plane as the
laser beam.
3. Allow enough space around the BeamSquared
hardware to direct the laser beam through the input
aperture.
4. Secure the optical train to the optical table with the
provided mounting clamps.
An example of a typical setup can be seen below. The
turning mirrors shown are optional accessories that are
critical to alignment.
The center of the input aperture is 3.212” (81.58mm) high when mounted in either orientation.

Install the Camera2.3.2
The camera imager is windowless and can be easily damaged if it comes in contact with any foreign
objects. Only clean the camera imager by gently blowing on it with clean dry air or nitrogen.
1. Remove the C-mount threaded insert from
the camera mounting clamp.
2. Point the camera to the floor and remove
the protective dust cover.
3. Thread the C-mount insert into the camera.
Take care not to cross thread the
components.
Keep the camera face down as you attach the threaded insert to prevent
dust from contacting the imager.
4. Insert the camera completely into the optical train and re-secure the screw on the camera mounting
clamp.
Orientation of the camera is not critical at this point and will be covered more in section 2.5.4.
Specific camera information can be found in Appendix C.
Re-secure the screw to hold the camera in
place on the optical train.

Connect BeamSquared2.3.3
1. Connect the USB cable on the
BeamSquared to an available USB
3.0 port on your PC.
2. Connect the short USB cable from
the Camera directly to the
BeamSquared Unit. (Connect the
Camera Power Supply if applicable.)
3. Plug the BeamSquared power supply
into a grounded A/C outlet.
4. When BeamSquared is connected for
the first time, a Found New
Hardware message appears. Wait
for a notice of successful
completion. If Windows reports a
failure to install a driver, see Chapter
7.
5. Launch the BeamSquared software
by double-clicking the BeamSquared
icon or launch from the Windows
Start button.
6. When the optical train initializes, the
translation table and attenuator
cycle the entire range of motion,
confirming the table and attenuator
are fully operational, and then sets
them to the home locations.
Only connect one Ophir-Spiricon device at a time. If multiple devices are connected to a single PC,
the camera or other components may not connect correctly.
The M
2-200 and M 2-200s required loading a configuration file specific to the wavelength, lens, and
camera in use. This data is now preprogrammed into each unit and the system employs the stored
calibration information as needed.
Do not align the laser through the BeamSquared until the beam has been properly attenuated per
section 2.4. Setting an unattenuated beam through the BeamSquared may damage the optics.