THORLABS HNL100R User manual

HNL100R, HNL100L, HNL150R,
HNL150L, HNL225R, HNL210L
Red HeNe Laser System
User Guide

Table of Contents
Chapter 1Warning Symbol Definitions..............................................................................................1
Chapter 2Safety....................................................................................................................................2
2.1.Safety Information...........................................................................................................2
2.1.1.Safety Summary....................................................................................................................2
2.1.2.Safety Information .................................................................................................................2
2.2.Safety Instructions ..........................................................................................................4
2.2.1.Before Initializing and Operating the Unit .............................................................................4
2.2.2.Laser Safety Precautions ......................................................................................................4 
Chapter 3Description...........................................................................................................................6
3.1.Laser Head .......................................................................................................................6
3.2.Laser Power Supply ........................................................................................................6
3.3.HeNe Laser Overview......................................................................................................7
3.3.1.HeNe Linewidth.....................................................................................................................7
3.3.2.HeNe Polarization .................................................................................................................9
Chapter 4Setup....................................................................................................................................10
4.1.Unpacking ......................................................................................................................10
4.1.1.Shipping Inventory ..............................................................................................................10
4.2.Mounting the Laser Head .............................................................................................11
4.3.Assembly .......................................................................................................................11
Chapter 5Operation.............................................................................................................................12
5.1.HeNe Power Supply ......................................................................................................12
5.1.1.Introduction..........................................................................................................................12
5.1.2.Remote Interlock Operation ................................................................................................12
5.1.3.Maintenance and Service....................................................................................................13
Chapter 6Troubleshooting.................................................................................................................14
6.1.Technical Failures .........................................................................................................14
6.2.Application Troubleshooting .......................................................................................14
6.2.1.Noise, Oscillations, and Fluctuation Sources......................................................................15
Chapter 7Specifications.....................................................................................................................16
Chapter 8Mechanical Drawing...........................................................................................................19
Chapter 9Regulatory...........................................................................................................................21
9.1.Waste Treatment is Your Own Responsibility............................................................ 21
9.2.Ecological Background ................................................................................................21
9.3.Compliance ....................................................................................................................22
Chapter 10Thorlabs Worldwide Contacts..........................................................................................23

Red HeNe Laser Systems Chapter 1: Warning Symbol Definitions
Rev C, March 29, 2017 Page 1
Chapter 1 Warning Symbol Definitions
Below is a list of warning symbols you may encounter in this manual or on your device.
Symbol Description
Direct Current
Alternating Current
Both Direct and Alternating Current
Earth Ground Terminal
Protective Conductor Terminal
Frame or Chassis Terminal
Equipotentiality
On (Supply)
Off (Supply)
In Position of a Bi-Stable Push Control
Out Position of a Bi-Stable Push Control
Caution: Risk of Electric Shock
Caution: Hot Surface
Caution: Risk of Danger
Warning: Laser Radiation
Caution: Spinning Blades May Cause Harm

Red HeNe Laser Systems Chapter 2: Safety
Page 2 22172-D02
Chapter 2 Safety
WARNING
Laser Radiation – Avoid Exposure to Beam – Class IIIb/Class 3B Laser Product.
2.1. Safety Information
2.1.1. Safety Summary
As defined by the Federal Register 21 CFR 1040.10 Laser Safety Standard, Thorlabs’ Helium Neon laser heads
are classified according to output power and wavelength. In compliance with this standard, certain performance
features and laser safety labels are provided on the product.
The American National Standards Institute publishes a laser safety standard for users, entitled American National
Standard for the Safe Use of Lasers (ANSI Z136.1). Thorlabs strongly recommends that laser users obtain and
follow the procedures described in this ANSI standard.
Copies may be obtained from:
A.N.S.I. Washington, DC. Headquarters
1819 L Street, NW (between 18th and 19th Streets), 6th floor
Washington, DC 20036
Tel: [phone]
Fax: [phone]
www.ansi.org
Laser Institute of America
13501 Ingenuity Drive, Suite 128
Orlando, FL 32826
Toll Free: [phone]
Telephone: [phone]
Fax: [phone]
www.laserinstitute.org
2.1.2. Safety Information
Classification
These laser heads do not connect directly to the mains, they are considered Installation
Category Type I. The included power supplies do connect directly to the mains, they are
considered Installation Category Type II.
The power supply provides protective earthing as one of the means of shock protection. The
following symbol is used to indicate a protective conductor terminal inside the unit.
Disconnecting from Line Power
The power supply power cord must always be accessible from the AC line-power source (receptacle). If the unit is
installed in a cabinet, the operator must be able to disconnect the unit from the line power by the system’s line-
power switch.

Red HeNe Laser Systems Chapter 2: Safety
Rev C, March 29, 2017 Page 3
Power Supply Line Power Requirements
The unit can operate from any single-phase AC power source that supplies 120 (no dash), 230 (-EC), or 100 (-JP)
VAC at a frequency range of 50 to 60 Hz. It draws 0.6 A maximum. The maximum power consumption is
dependent on the configuration of each system.
Laser Safety Parameters
The parameters for the laser system are outlined in the table below, followed by classification warning labels. See
specification tables for classifications specified by the Center for Devices and Radiological Health (CDRH), a
division of the Food and Drug Administration (FDA).
Item # HNL100R(L) HNL150R(L) HNL210L HNL225R
Wavelength 633 nm 633 nm 633 nm 633 nm
Laser Classification Class IIIb (CDRH)/3B (IEC)
Min Output Power 10.0 mW 15.0 mW 21.0 mW 22.5 mW
Beam Diameter
(TEM00, 1/e2 points ±3%)
Ø0.68 mm Ø0.70 mm Ø0.70 mm Ø0.70 mm
DANGER
LASER RADIATION
AVOID EXPOSURE TO BEAM
CLASS IIIb LASER PRODUCT (CDRH)
CLASS 3B LASER PRODUCT
WAVELENGTH 633 nm
MAXIMUM POWER <35 mW
IEC60825-1:2007 ed2.0
AVOID EXPOSURE
LASER RADIATION
IS EMITTED FROM
THIS APERTURE

Red HeNe Laser Systems Chapter 2: Safety
Page 4 22172-D02
2.2. Safety Instructions
WARNING
Use of controls or adjustments or performance of procedures other than those specified herein may
result in hazardous radiation exposure. Avoid unnecessary exposure to laser or collateral radiation
that exceeds the acceptable emission limits listed in the safety regulation guidelines 21 CFR
Subchapter J 1040.10 and 1040.11. This federal regulation is administered by the National Center for
Devices and Radiological Health under the Food and Drug Administration.
The following safety instructions must be observed whenever the unit is operated, serviced, or repaired. Failure to
comply with any of these instructions or with any precaution or warning contained in the user’s manual is in direct
violation of the standards of design, manufacture, and intended use of the unit. Thorlabs’ assumes no liability for
the customer’s failure to comply with any of these safety requirements.
2.2.1. Before Initializing and Operating the Unit
Inspect the unit for any signs of damage, and read the user’s guide thoroughly.
Install the unit as specified in the Setup section on page 10.
Ensure that the unit and any devices or cords connected to it are properly grounded.
2.2.2. Laser Safety Precautions
It is recommended that all persons who use or are near lasers be aware of the potential hazards.
Warning
The starting and operating voltages of the laser head are lethal and are specified herein. Ensure that
the power supply is turned off and unplugged before attempting to connect or disconnect the
lasers.
Do not access the interior of the power supply.
The lasers and the power supplies are not serviceable units.

Red HeNe Laser Systems Chapter 2: Safety
Rev C, March 29, 2017 Page 5
Warning
To avoid the risk of injury or death,
always observe the following precautions before initializing the unit:
Never look into the end of an optical cable connected to an optical output device that is operating. Laser radiation is
invisible, and direct exposure can severely injure the human eye.
Eye and skin exposure to direct or scattered laser radiation is hazardous and is considered potentially extremely
harmful.
Install the laser in an enclosed area with access restricted to trained personnel. Clearly label the area and mark the
entrance with the class of laser (Class II, IIIa, or IIIb).
Never leave the laser on and unattended.
If the laser has a key switch on the power supply front panel, the key must be inserted and turned to enable the laser
to operate. The key is captive in the operational position. Remove the key from the laser when not in use or
unattended. Store the key in a safe place.
Limit access to the laser to personnel who are familiar with the equipment. Ensure that the laser is not assembled,
operated, or repaired by inexperienced or untrained personnel.
Ensure that all mirrors and optics used are securely positioned and fixed to prevent movement. Prevent stray
reflections from surfaces at all times.
Do not allow reflective objects to be placed in the laser beam. Laser light scattered from a reflective surface can be as
damaging as the original beam. Objects such as rings, watchbands, and metal pens or pencils can be hazardous.
Install the laser so that the laser beam is not at eye level.
Terminate the laser beam path with a suitable power meter or non-reflecting beam stop. Enclose beam stops where
possible. Consult a power meter or the beam stop manufacturers’ operating manual for proper usage.
Suitable eye protection must be worn at all times when laser output is possible.
Connect the power cord only to a power outlet equipped with a protective earth contact. Never connect to an
extension cord that is not equipped with this feature.
Do not interrupt the protective earth grounding. Any such action can lead to a potential shock hazard that can result in
serious personal injury.
Disconnect the power cord from the unit before adding or removing any components. Do not rely on electrical safety
devices or interlocks.
Some electrical components within the products may maintain electrical charge even when unplugged.
After unplugging products from the ac mains, wait a minimum of 1 minute before disconnecting the laser head from
the power supply. The emission indicator on the power supply should be off.
WARNING: When disconnecting a laser head from a power supply there may be a residual charge remaining within
the laser head and present at the exposed tips of the HV connector. Release any excess charge by shorting the tips
of the connector to a metal surface before additional handling.
Do not use the unit outdoors. To prevent potential fire or shock hazard, do not expose the unit to any source of
excessive moisture.
Operating the unit in the presence of flammable gases or fumes is extremely hazardous.
Never remove covers or panels from the units.
Do not perform any operating or maintenance procedure that is not described in the user’s manual.

Red HeNe Laser Systems Chapter 3: Description
Page 6 22172-D02
Chapter 3 Description
Thorlabs’ line of cylindrical, high-power, red (632.8 nm) helium-neon (HeNe) gas lasers have stable output
powers from 10.0 to 22.5 mW and a fundamental Gaussian beam. Depending on the model chosen, the output
beam will be either linearly polarized or randomly polarized (unpolarized). The state of polarization in a randomly
polarized laser beam is not truly an unpolarized source, but rather a single state of polarization that changes on a
small timescale.
3.1. Laser Head
This laser head comes equipped with a manual shutter installed in the front bezel of the laser housing (see Figure
1 below). The front bezel has four 4-40 UNC holes to secure the optional accessory mounting ring and other
industry standard HeNe accessories. This laser also comes with a 6 ft long, high-voltage cable for connecting to
the power supply. This particular laser head is designed to operate at an optimum performance level when used
with the required Thorlabs power supply.
Figure 1 Laser Head
3.2. Laser Power Supply
The laser includes a power supply that is specially designed to be used with the HeNe laser and is CE-certified.
The power supply is enclosed in a protective housing and is CDRH compliant with a built-in 3 to 5 second time
delay, an Alden high-voltage connector (see Figure 2 below), a key lock switch with two removable keys, a power
on indicator1, and a remote interlock connector. The power supply comes configured for one of three local mains
voltage: 120 VAC (no dash), 230 VAC (-EC), or 100 VAC (-JP).
Figure 2 High Voltage Alden Plug
1 The “Laser On” indicator will come on when the key is turned on. It does not indicate the laser is on, lasing, or the power supply is working. It
only indicates that there may be power going to the laser head.
Manual Beam Shutter
Laser Aperture
4 M3 x 0.5 mm
Mounting Holes

Red HeNe Laser Systems Chapter 3: Description
Rev C, March 29, 2017 Page 7
3.3. HeNe Laser Overview
A helium-neon laser, typically called a HeNe laser, is a small
gas laser with many industrial and scientific uses. The
primary wavelength they are used at is 632.8 nm, in the red
portion of the visible spectrum.
The gain medium of the laser is a mixture of helium and neon
gases in a 5:1 to 20:1 ratio that is contained at low pressure
in a sealed glass tube. The excitation source for these lasers
is a high-voltage electrical discharge through an anode and
cathode at each end of the glass tube. The optical cavity of
the laser consists of a flat, high-reflecting mirror at one end of
the laser tube and an output coupler mirror with
approximately 1% transmission at the other end.
Figure 1 Optical Resonator Cavity
Typical HeNe Parameters
Beam Diameter (D) 1 mm
Cavity Length (L) 0.15 m (0.5 mW) to 1 m (50 mW)
Reflectivity at High Reflector (HR) >99.99%
Transmission at Output Coupler (OC) ~1%
HeNe lasers tend to be small, with cavity lengths of around 15 cm up to 0.5 m and optical output powers ranging
from 1 mW to 100 mW. Thorlabs offers output powers up to 22.5 mW.
3.3.1. HeNe Linewidth
A red HeNe laser wavelength is 632.816 nm in air, though it is often reported as either 632 nm or 633 nm. The
wavelength gain curve is actually made of several longitudinal modes that fluctuate within the range due to
thermal expansion of the cavity and other external factors.
The linewidth of a HeNe laser is specific to the application. The axial mode structure of the HeNe laser is
characterized by the number of modes, the free spectral range (FSR), and the Doppler width (see Figure 2 on
page 6). The linewidth of individual axial modes is usually small (~kHz) and is primarily determined by external
factors and measurement timescales rather than fundamental laser parameters. In most interferometric
applications, the most relevant parameter is the coherence length, which is determined by the axial modes that
are furthest apart. For a red HeNe laser, the coherence length is approximately 30 cm.
D
L
Anode
High
Reflector
Output
Coupler
Helium-Neon Gas Mixture
Glass Tube
Laser Bore Tube
Cathode
HeNe Applications
Metrology
Cleanroom Monitoring Equipment
Food Sorting
Flow Cytometry
Confocal Microscopy
Imaging and Medical Equipment
Opacity Monitoring
Alignment
Maritime Visual Guidance Systems

Red HeNe Laser Systems Chapter 3: Description
Page 8 22172-D02
Figure 2 HeNe Gain Curve Showing Cavity Modes
The laser process in a HeNe laser starts with the collision of electrons from the electrical discharge with the
helium atoms in the gas. This excites helium from the ground state to a long-lived, metastable excited state.
Collision of excited helium atoms with ground-state neon atoms results in excited neon electrons.
Figure 3 HeNe Energy Levels
The number of neon atoms entering the excited states builds up until population inversion is achieved.
Spontaneous and stimulated emission between the states results in emission of 632.82 nm light along with other
emission wavelengths. From these states, the electrons quickly decay to the ground state. The HeNe laser’s
power output is limited because the neon upper level saturates with higher current, while the lower level varies
linearly with current.
The laser cavity can be designed with the correct mirrors and length to promote other wavelengths of laser
emission. There are infrared transitions at 3.39 μm and 1.15 μm wavelengths, and a variety of visible transitions,
Neon Gain
Curve
FWHM ~1.5 GHz
Frequency
Gain/Output Power
Lasing
Cavity Modes
Lasing
Threshold
FSR ~1000 MHz
Short (0.2 m) Laser
FSR ~200 MHz
Long (1 m) Laser
Energy (Electron Volts)
Ground States
Metastable Collision
Metastable Collision
e Impact
3S2
1S
3S2S2
1S
2P4
3P4
(20.66 eV)
(20.30 eV)
(20.61 eV)
(19.78 eV) (19.78 eV)
(18.70 eV)
1
2
5
10
21
20
19
18
17
16
(16.70 eV)
(3391.2 nm Laser)
(632.8 nm Laser)
(1152.3 nm Laser)
Diffusion
Helium Neon

Red HeNe Laser Systems Chapter 3: Description
Rev C, March 29, 2017 Page 9
including a green (543.365 nm, sometimes called GreeNe laser), a yellow (593.932 nm), a yellow-orange
(604.613 nm), and an orange (611.802 nm) transition. The typical red, 633 nm wavelength output of a HeNe laser
actually has a much lower gain compared to other wavelengths, such as the 1.15 μm and 3.39 μm lines.
Figure 4 HeNe Visible Laser Lines
3.3.2. HeNe Polarization
Unpolarized (Randomly Polarized) Beam
The output of an unpolarized HeNe laser consists of a rapidly fluctuating, linearly polarized beam whose
polarization orientation changes on a nanosecond time scale. Unpolarized lasers are ideal for applications where
there are no polarizing elements in the beam path. Depending on the time scale of an application, large power
fluctuations are possible.
Linear Polarized Beam
The state of polarization in a polarized HeNe laser beam is linear, making these lasers ideal for polarization-
sensitive applications.
500 550 650
Wavelength (nm)
HeNe Visible Laser Lines
750600 700

Red HeNe Laser Systems Chapter 4: Setup
Page 10 22172-D02
Chapter 4 Setup
4.1. Unpacking
Inspect the packing container for any damage that may have occurred during shipment. Contact your local
Thorlabs customer service office for assistance. Packing materials are specifically designed to protect against
shipping damage. Please keep this container and reuse it if your system needs to be returned to Thorlabs for
service or evaluation.
Carefully remove the laser system from the packing container. Inspect for damage, including dents and scratches.
There should not be anything rattling around inside the laser head. Rarely, during shipping, the glass tube may
break.
Figure 3 Laser System
4.1.1. Shipping Inventory
The equipment included in this shipment should match the packing slip attached to the box. Verify that the correct
product was shipped to you by identifying the item number on the box. If the shipment is incomplete, or if an
incorrect item was shipped to you, please notify Thorlabs immediately.
This package should contain:
Cylindrical Laser Head
Power Supply
2 Keys for Power Supply
Remote Interlock for Power Supply
User Guide and Quick Start Guide
Power Supply Module Laser Head
Laser head with manual shutter and
power cord with Alden connector
Accessories
From left to right: power switch
keys, interlock connector

Red HeNe Laser Systems Chapter 4: Setup
Rev C, March 29, 2017 Page 11
4.2. Mounting the Laser Head
The cylindrical construction of the laser head allows for easy mounting in ring clamps, V-blocks, or similar
mounting hardware without affecting the laser’s alignment. Use caution when clamping onto the laser, as too
much pressure can damage the aluminum housing or cause misalignment. The front bezel has four 4-40 UNC
holes to secure standard HeNe optional accessories. The laser head should always be secured in place and not
allowed to move freely. Not only can the laser roll off the work surface and break, but the laser emission can be a
health hazard.
See the table below for the recommended number of
mounting points. It is recommended to use V-block
mounts (see figure to the right). Thorlabs offers fixed
and kinematic mounts.
HeNe Laser Length
Number of V-block
Mounts
Number of Ring
Clamps
7 – 16" 1 2
16"+ 2 3
4.3. Assembly
It is suggested that the HeNe Laser Quick Start Guide (a separate document found enclosed with the laser) be
used to assemble the laser system. Listed below are the steps needed to assemble the laser system.
This laser system includes a fixed-voltage power supply that is factor-set for either 120 (no dash), 230 (-EC), or
100 VAC (-JP) operation. The laser must be purchased correctly configured for the appropriate regional current.
The proper mains voltage cord must also be used.
WARNING
Never remove the Alden plug from the power supply while the power supply is plugged into the
mains. Doing so may result in arcing that could damage the laser head or power supply.
1) Make sure the laser head is secured to your work surface and pointed safely away from people and
directed into a beam block, beam dump or similar nonreflective surface.
2) Plug the high-voltage cable from the laser into the rear of the power supply. Confirm that the Alden plug is
well-seated. The first few times the plug is inserted, it may require more force than expected. Failure to
plug the connector all the way in can result in the laser failing to lase or arcing and damage to the power
supply or laser head.
3) Insert the shorting remote interlock connector into the back of the power supply. Note that the plug only
goes in one way. Also note that the LED light on the front of the power supply will light even if the
interlock is not inserted.
4) Plug the AC connector into the mains outlet.
5) Insert the key into the front panel of the power supply.
HNL150L in two C1502
V-Clamp Mounts

Red HeNe Laser Systems Chapter 5: Operation
Page 12 22172-D02
Chapter 5 Operation
To operate the laser system, follow the following procedures:
1) Make sure that the laser is pointing safely away from people and is securely mounted and directed into a
beam block, beam dump or similar nonreflective surface.
2) Open the aperture by turning the screw 90° in either direction using a flat head screwdriver.
Figure 4 Laser Shutter Control, Picture shows the Shutter CLOSED.
3) Turn the key switch on the power supply on. The “Laser On” LED indicator will light.
Note: There is a 3 to 5 second CDRH safety delay before the voltage turns on.
5.1. HeNe Power Supply
5.1.1. Introduction
The HeNe power supply is a turn-key power supply for HeNe laser tubes that incorporates all of the appropriate
safety features required by US federal regulations. Note that the power supply that came with your HeNe
laser is specifically designed to be used with that model of HeNe lasers and is not compatible with other
HeNe laser models.
This unit is RoHS compliant.
5.1.2. Remote Interlock Operation
To use the remote interlock connector, the metal pin needs to be removed, the top of plug taken out and the
shorting conductor from the connector removed. The connector may then be wired into the user’s interlock
system. Be sure to reinstall the plastic safety cover over the interlock before use. The interlock is at AC line
potential and proper care must be taken to use the correct wire gauges, insulation types, etc.
The voltage on this connector is the same as the AC line voltage of your pre-configured power supply. Only the
provided connector should be used as an interlock and never anything else. Please contact your local tech
support office for a replacement connector.
WARNING
Use of controls, adjustments, or performance of procedures, other than those specified herein,
may result in hazardous radiation exposure.
Shutter Control Screw
The shutter is closed when the switch
is slid to the right as shown in picture.
The shutter is opened when the
switch is slid to the left.

Red HeNe Laser Systems Chapter 5: Operation
Rev C, March 29, 2017 Page 13
Figure 5 Front of the Power Supply Module
Figure 6 Back of the Power Supply Module
5.1.3. Maintenance and Service
The power supply power supply contains no user-serviceable parts. Return the power supply to Thorlabs for
service.
2 Position Key Switch
Laser On LED
LED only indicates the power supply is on
and that the laser MAY be emitting light.
High Voltage Alden
Connector
Remote Interlock
Connecto
r
Power Cord

Red HeNe Laser Systems Chapter 6: Troubleshooting
Page 14 22172-D02
Chapter 6 Troubleshooting
6.1. Technical Failures
Problem Fix
No light is being emanating from
the laser.
Make sure that the aperture is open.
Check to make sure that
the Alden plug is firmly seated into the power supply (it may
take more force to push the plug in all the way the first few
times),
the interlock connector is plugged in and fully seated,
the power supply is plugged into a working outlet, and
the aperture is open.
Note: There is a built in CDRH safety delay of 4 - 5 seconds
before the laser starts to lase after turning the key switch
The laser does not work and
there is something rattling
around inside the laser head
tube.
The glass gas tube may have broken during shipping. Please contact
your local tech support office for help.
The power supply does not turn
on.
The power supply Laser On
Indicator does not light.
Make sure the power supply is plugged in.
The laser has low output power. The laser requires 10 minutes to meet published specifications. Make
sure to let it warm up.
Make sure that the laser is mounted correctly. See page 11 for proper
mounting techniques.
6.2. Application Troubleshooting
Some sources of trouble of a HeNe laser do not come from the laser failing or being out of spec. In some cases,
these laser are not suited to the application. One common mis-application comes from a HeNe laser, especially a
low power laser (~0.5 mW), being used in a metrology application.
Environment is an important consideration as well. Dirty environments can cause the optics to become
contaminated and the power output to drop below expected levels. Unstable output beams can be caused by
noisy environments with large sources of vibrations. Proper mounting on an optical table can reduce the effects of
ambient vibrations. Temperature is also a factor. If the environment where the laser is being used fluctuates in
temperature, the output power can experience a large amplitude change. Even blowing on the laser tube can
cause the output power to fluctuate significantly.
Randomly polarized lasers are actually rapidly changing, single polarization lasers. When averaged over time, the
light emitted from these lasers appears randomly polarized. However, any polarization optics in the path
(intentional or unintentional) can cause large variations in the output power. Only polarized lasers should be used
in applications that involve polarization optics.
While HeNe lasers are less sensitive to variations caused by back reflections, they are not immune to them. Large
retro-reflections back into the laser can cause unpredictable power changes. A free-space isolator can be used to
reduce or eliminate these effects. If possible, only a small angular deviation is needed to eliminate the back
reflections.
These HeNe lasers are ill suited to any application or experiment where a single frequency or long coherence
length is required.

Red HeNe Laser Systems Chapter 6: Troubleshooting
Rev C, March 29, 2017 Page 15
6.2.1. Noise, Oscillations, and Fluctuation Sources
There are many sources of noise, oscillations and fluctuations of the output of a HeNe laser. One of the most
common is from longitudinal modes drifting into and out of the gain curve. The frequency of these fluctuations
vary from less than a Hz to as high as several kHz, depending on the stability of the environment.
Other, more constant sources of fluctuations are from the following (with corresponding frequencies):
Line Noise from AC High-Voltage Power Supplies (50/60 Hz, 100/120 Hz, etc.)
Switching Noise from DC High-Voltage Power Supplies (40 kHz)
Plasma Oscillation (Tens of MHz)
Transverse Mode Beat Notes (Hundreds of MHz)
Axial Mode Beats (at FSR, Hundreds of MHz)

Red HeNe Laser Systems Chapter 7: Specifications
Page 16 22172-D02
Chapter 7 Specifications
Item # HNL100L HNL100R
Wavelength 632.8 nm
Min Output Power (TEM00, 633 nm) 10.0 mW
Min Polarization Ratio 500:1 Random
Beam Diameter (TEM00, 1/e points + 3%) 0.68 mm
Beam Divergence (TEM00, + 3%) 1.2 mrad
Mode Purity (TEM00) >95%
Longitudinal Mode Spacing 320 MHz
Max Noise (RMS) (30 Hz to 10 MHz)2 1.0%
Max Drift with Respect to Mean Power,
Over 8 hr ±3.0%
Max Mode Sweeping Contribution 2%
Beam Pointing Stability (25 C)
From Cold Start <0.10 mrad
After 15 min Warm-up <0.02 mrad
Operating Voltage (±100 V) 3100 VDC
Operating Current (±0.1 mA) 6.5 mA
Max Starting Voltage 10 kVDC
Physical/Mechanical Characteristics HNL100L(R)
Max Warm-up Time (95% power) 15 min
Expected Operating Lifetime >40,000 hr
Storage Lifetime Indefinite (Hard-Sealed)
Static Alignment Center to Outer Cylinder within ±0.01".
Parallel to Outer Cylinder within ±1 mR
Laser Head Weight 1.5 lbs (0.68 kg)
Environmental HNL100L(R)
Temperature, Operating -40 to 70 °C
Temperature, Non-operating -40 to 150 °C
Altitude, Operating 0 to 10,000 ft
Altitude, Non-Operating 0 to 70,000 ft
Relative Humidity (non-condensing) 0 to 100%
Shock 25 g for 11 ms, 100 g for 1 ms
Safety HNL100L(R)
CDRH/IEC 60825-1 Class IIIb/3B
2TEM00 version only.

Red HeNe Laser Systems Chapter 7: Specifications
Rev C, March 29, 2017 Page 17
Item # HNL150L HNL150R
Wavelength 632.8 nm
Min Output Power (TEM00, 633 nm) 5.0 mW
Min Polarization Ratio 500:1 Random
Beam Diameter (TEM00, 1/e points + 3%) 0.70 mm
Beam Divergence (TEM00, + 3%) 1.15 mrad
Mode Purity (TEM00) >95%
Longitudinal Mode Spacing 257 MHz
Max Noise (RMS) (30 Hz to 10 MHz)3 0.5%
Max Drift with Respect to Mean Power,
Over 8 hr ±2.0%
Max Mode Sweeping Contribution 1%
Beam Pointing Stability (25 C)
From Cold Start <0.20 mrad
After 15 min Warm-up <0.03 mrad
Operating Voltage (±100 V) 3800 VDC
Operating Current (±0.1 mA) 6.5 mA
Max Starting Voltage 10 kVDC
Physical/Mechanical Characteristics HNL150L(R)
Max Warm-up Time (95% power) 20 min
Expected Operating Lifetime >40,000 hr
Storage Lifetime Indefinite (Hard-Sealed)
Static Alignment Center to Outer Cylinder within ±0.01".
Parallel to outer Cylinder within ±1 mR
Laser Head Weight 2.6 lbs (1.2 kg)
Environmental HNL150L(R)
Temperature, Operating -40 to 70 °C
Temperature, Non-operating -40 to 150 °C
Altitude, Operating 0 to 10,000 ft
Altitude, Non-Operating 0 to 70,000 ft
Relative Humidity (non-condensing) 0 to 100%
Shock 25 g for 11 ms, 100 g for 1 ms
Safety HNL150R(L)
CDRH/IEC 60825-1 Class IIIb/3B
3TEM00 version only.