THORLABS DMH40-F01 User manual

Piezoelectric Deformable Mirror
2021
DMH40(/M)-F01,
DMH40(/M)-P01
Operation Manual

Version:
Date: 1.1 15-Apr-2021
Copyright © 2021 Thorlabs

Foreword
Contents
1 General Information 1
11.1 Ordering Codes and Accessories
21.2 Requirements
21.2.1 Software Requirements
21.2.2 Hardware Requirements
2 Operating Principle 3
32.1 Mirror
52.2 Segment Structure
62.3 Closed Loop Control
82.4 Hysteresis of Piezoelectric Materials
92.5 Creep of Piezoelectric Materials
122.6 Relaxing the Mirror
3 Getting Started 13
133.1 Parts List
4 Operation 14
144.1 Operating Elements
144.2 Installing Software
154.3 Mounting
154.4 First Steps
164.5 Out-of-the-Box Test
174.6 Software Deformable Mirror
174.6.1 GUI Header
184.6.2 Menu Bar
214.6.3 Toolbar
224.6.4 Common Settings
234.6.5 Display Mirror Control
244.6.5.1 Individual Segment Control
244.6.5.2 Control in Arbitrary Groups of Segments
254.6.6 Control Panel
254.6.6.1 Zernike Control
274.6.6.2 Mirror Manipulation
284.6.6.3 Control Loop Settings
294.6.7 Color Bar
304.6.8 Status Bar
314.6.9 Display Mirror Temperature
324.6.10 The Configuration File
334.7 Closed Loop Control

5 Write Your Own Application 34
375.1 Instrument driver 32bit on 32bit systems
385.2 Instrument driver 32bit on 64bit systems
405.3 Instrument driver 64bit on 64bit systems
6 Maintenance and Service 41
416.1 Version Information
436.2 Troubleshooting
7 Appendix 46
467.1 Technical Data
497.2 Analog Feedback Connector
507.3 About Zernikes
517.4 Dimensions DMH40-xxx (Imperial)
527.5 Dimensions DMH40/M-xxx (Metric)
527.6 Safety
537.7 Return of Devices
547.8 Certifications and Compliances
557.9 Warranty
557.10Copyright and Exclusion of Liability
567.11References
577.12Manufacturer Address
587.13Thorlabs Worldwide Contacts and WEEE policy

© 2021 Thorlabs
We aim to develop and produce the best solutions for your
applications in the field of optical measurement techniques. To help
us to live up to your expectations and constantly improve our
products, we need your ideas and suggestions. We and our
international partners are looking forward to hearing from you.
Thorlabs GmbH
Warning
Sections marked by this symbol explain dangers that might result in
personal injury or death. Always read the associated information
carefully before performing the indicated procedure.
Please read this advice carefully!
This manual also contains "NOTES" and "HINTS" written in this form.
Attention
Paragraphs preceded by this symbol explain hazards that could
damage the instrument and the connected equipment or may cause
loss of data.
Note

© 2021 Thorlabs1
DMH40
1 General Information
The Thorlabs' Piezoelectric Deformable Mirror DMH40 is used to correct distorted wavefronts
that result from common sources of wavefront aberrations, such as astigmatism and coma.
The Thorlabs DMH40 Deformable Mirror consists of a piezoelectric disk with a segmented back
electrode glued to a glass substrate carrying the continuous reflective surface. The segmented
back electrode controls a number of independent mirror segments. Each segment area can be
forced to perform a local concave or convex bending, depending on the applied voltage.
Thereby the mirror can assume any desired shape to compensate for distorted wavefronts.
Besides individual or grouped segment control, the Thorlabs Deformable Mirror software
provides pre-defined voltage patterns for generation of Zernike function shapes. An adaptive
control algorithm based on these Zernike coefficients allows closed loop operation in conjunc-
tion with a feedback signal from our Shack-Hartmann wavefront sensors.
Each DMH40 deformable mirror has a Ø14 mm pupil and is available with one of two optical
coatings: UV-Enhanced Aluminum for 250 nm to 450 nm wavelength or Protected Silver for 450
nm to 20 mm wavelength.
Compared to the Thorlabs deformable mirror DMP40, the DMH40 has a more than 2 fold larger
stroke (hoisting capacity) resulting in a more than 2 fold curvature of the mirror. While, the
DMP40 can tilt the mirror due to its outer arms, the DMH40 can be tilted by using a kinematic
mount.
Attention
Please find all safety information and warnings concerning this product in the chapter Safety
in the Appendix.
1.1 Ordering Codes and Accessories
Item#
Short Description
DMH40-F01
Piezoelectric Deformable Mirror, UV-Enhanced Aluminum, 14 mm Pupil Dia-
meter, Imperial
DMH40/M-F01
Piezoelectric Deformable Mirror, UV-Enhanced Aluminum, 14 mm Pupil Dia-
meter, Metric
DMH40-P01
Piezoelectric Deformable Mirror, Protected Silver, 14 mm Pupil Diameter, Im-
perial
DMH40/M-P01
Piezoelectric Deformable Mirror, Protected Silver, 14 mm Pupil Diameter,
Metric
Recommended Accessories:
For Closed Loop Control setups, we recommend Thorlabs Wavefront Sensors (WFS) and Mi-
crolens Arrays (MLA) that are offered in combination.
Wavefront Sensor
(WFS Item# Prefix)
Short description
WFS20
High Speed Shack-Hartmann Wavefront Sensor
WFS30
General Purpose Shack-Hartmann Wavefront Sensor
WFS40
Large Area Shack-Hartmann Wavefront Sensor
52

© 2021 Thorlabs
1 General Information
2
Microlens Arrays:
Microlens Arrays
(WFS Item# Suffix)
Short description
-5C
based on Thorlabs MLA150-5C
-7AR
based on Thorlabs MLA150-7AR
-14AR
based on Thorlabs MLA300-14AR
1.2 Requirements
These are the requirements for the PC intended to be used for operation of the DMH40.
1.2.1 Software Requirements
The Thorlabs Deformable Mirror software is compatible with the following operating systems:
·Windows®7 SP1 and later (32-bit, 64-bit)
·Windows®8.1 (32-bit, 64-bit)
·Windows®10 (32-bit, 64-bit)
For operation of the DMH40, Microsoft®.Net Framework version 4.6.2 or higher must also be
installed. This software comes with the Thorlabs Deformable Mirror software installation pack-
age, available for download on the software tab of the Piezoelectric Deformable Mirror website.
For the Control Loop operation a Thorlabs Wavefront Sensor with a software version of 5.0
and later is required. For optimal performance, please use the latest software version available
online.
1.2.2 Hardware Requirements
CPU: 2 GHz or higher
RAM: 4 GB
Graphic card: 256 MB memory (shared)
Graphic resolution: min.: 1024 x 768; recommended: 1280 x 800
Hard disk: 1.2 GB (32 bit) / 2.6 GB (64 bit) free storage space
Interface: USB 2.0 port, USB cable according the USB 2.0 specification
33

© 2021 Thorlabs3
DMH40
2 Operating Principle
DMH40 structure - rear view
showing 40 mirror segments
The heart of the Thorlabs DMH40 is a deformable mirror. It is comprised of a glass substrate
with a reflective coating that has a thin piezo ceramic disk with segmented electrodes glued to
the back side.
The mirror is mounted via 3 mounting joints shown above.
2.1 Mirror
Cross section of the DMH40 inner mirror
The above sketch shows a simplified cross section of the inner mirror. The common electrode
for all segments is connected to ground (0 V), while the back side electrode is divided into 40
single segments that can be controlled individually by a DC voltage in the range 0 – 300 V
each.

© 2021 Thorlabs
2 Operating Principle
4
During the gluing process, a control voltage of 150 V is applied to all segment electrodes. For
this reason, a flat mirror surface will appear at a control voltage level of 150 V, applied to all
segments. At voltages <150 V, the piezo material above the corresponding electrode will ex-
pand, leading to a local concave shape, while a voltage >150 V shrinks the piezo and leads to a
local convex shape:
Applying a voltage to a piezo segment
Applying the same voltage higher or lower than 150 V to all 40 electrodes results in a pure
spherical mirror shape. An arbitrary surface shape can be generated by applying a defined
voltage pattern.
Note
The mirror will be nearly flattened after connecting it to the power supply and to a PC with the
installed Thorlabs Deformable Mirror software! The reason is that the software will initialize the
hardware only after PC connection is made. Whenever no power is connected to the DMH40,
the mirror will be concave (0 V position).

© 2021 Thorlabs5
DMH40
2.2 Segment Structure
View onto the mirror surface
Electrode numbering is shown for a mirror with the reflective surface facing the viewer.
Note
The instrument driver software accepts zero-based segment indices in the range 0 – 39, while
the user interface in the software refers to the numbering as shown in the above diagram.
The segments 25 to 40, surrounding the mirror pupil, are used to get defined curvatures even
at the pupil's rim. This improves the quality and amplitude of the Zernike terms generation.