THORLABS EXLUS-HD1 Manual de usuario
SPATIAL LIGHT MODULATORS
Applications
Wavefront Correction
Optical Trapping
Beam Steering
Pulse Shaping
Adaptive Optics
Holography
Laser Processing
Lithography
Click to Enlarge
Each Exulus SLM features multiple 8-
32 (M4) taps for post mounting. For a
list of items used in this setup, see the
App Note
tab.
Click to Enlarge
The Exulus SLMs (excluding the high-
power SLMs) are provided with a
magnetic cover; when the SLM is in
use, the cover can be attached to the
designated area on the housing (sides
for the HD1 models and back for the
Features
Liquid Crystal on Silicon (LCoS) with Reflective Coating
Panel Resolutions: 1920 x 1080 or 1920 x 1200
Operating Wavelengths: 400 - 850 nm, 650 - 1100 nm, or
1550 nm
High-Power Models Available for 400 - 850 nm or 650 - 1100 nm Operating Ranges
All-in-One and Separate-Panel Mounting Configurations
Liquid Cooling Module Included on SLM Head
Fill Factor: >90% (Varies by Model)
Independent Horizontal and Vertical SLM Panel Tilt Adjustments (Standard SLM
Models Only)
Trigger Output for Timing Control of Other Devices (All Models Except
EXULUS-HD1)
Fast Frame/Refresh Rates up to 180 Hz (EXULUS-HD1 Only, Using
Frame Boost)
Customizations Available:
Panel and Controller in Separate Units (Standard SLM Models
Only)
Other Retardance Ranges (Contact Tech Support for Details)
Thorlabs' Exulus® Spatial Light Modulators (SLMs) employ Liquid Crystal on
Silicon (LCoS) technology to produce high-resolution, high-speed reflective
phase modulation with individually addressable pixels. This phase control is
OVER VIEW
Reflective 2D Phase Only Spatial Light Modulators (SLMs)
400 - 850 nm, 650 - 1100 nm, or 1550 nm Operating Wavelengths
Available Resolutions: 1920 x 1080 or 1920 x 1200
Highly Stable Phase Control with Minimal Flickering
►
►
►
►
EXULUS-HD3HP
Removable SLM Head,
1920 x 1200 (WUXGA),
650 - 1100 nm
Image Generated by SLM Using Computer-
Generated Hologram Projection. For Details, See
EXULUS-HD1
1920 x 1080 (Full HD),
400 - 850 nm
EXULUS-HD1 - November 22, 2023
Item EXULUS-HD1 was discontinued on November 22, 2023. For informational purposes, this is a copy of
the website content at that time and is valid only for the stated product.
HD2, HD3, and HD4 models).
Video Insight: Calibrate a Spatial Light Modulator (SLM) for Phase Delay
Watch a demonstration of an interferometric method for calibrating the phase delay of reflective SLMs.
Key Specificationsa
Item #
Suffix
Operating
Wavelength
Panel
Resolution
Fill
Factor
Phase / Retardance
Rangeb
Frame
Rate
Output
Trigger
Liquid Cooling
Module
Separable SLM
Panel
HD1 400 - 850 nm 1920 x 1080
(Full HD) >93% 2π at 633 nm (Standard)
4.7π at 532 nm (Extended)
60 Hz or
180 HzcN/A - -
HD2 400 - 850 nm 1920 x 1200
(WUXGA) >92% π or 2π at 633 nmd60 Hz
Yes
(SMA)
- -
HD3 650 - 1100 nm 1920 x 1200
(WUXGA) >92% π or 2π at 1064 nmd60 Hz - -
HD4 1550 nm 1920 x 1200
(WUXGA) >92% π or 2π at 1550 nmd60 Hz - -
HD2HP 400 - 850 nm 1920 x 1200
(WUXGA) >92% π or 2π at 633 nmd,e 60 Hz
HD3HP 650 - 1100 nm 1920 x 1200
(WUXGA) >92% π or 2π at 1064 nmd,e 60 Hz
Complete specifications may be found on the Specs tab.
highly stable with minimal fluctuations and minimal crosstalk with adjacent
pixels. For maximum phase shift values, refer to the
table to the upper right. These spatial light modulators
provide far more pixels than lower-order phase
modulators such as segmented or deformable mirrors.
For applications requiring improved thermal stability
and high-power handling (≤200 W/cm) in the 400 nm to
850 nm or 650 nm to 1100 nm wavelength ranges, high-power SLMs are available.
Exulus spatial light modulators are driven by an input video signal and operate as a general Full HD or WUXGA. They are bundled with a software GUI that
provides complete control over the device. Different driving modes are supported by the software, including full frame, image input, video input, Fresnel lens,
diffraction, and computer-generated holography (CGH). The CGH mode also allows tilting and focusing effects to be overlaid onto a pattern. The GUI enables
quick switching between operating modes, as well as allowing images, videos, and patterns to be uploaded to the panel. For more details on the operating
modes, please see the Software and App Note tabs.
Standard Models
Each standard spatial light modulator (EXULUS-HD1, -HD2, -HD3, and -HD4) includes a built-in SLM panel with independent horizontal and vertical tilt
adjustment of ±3.2°. Locking rings are installed to fix the adjustment settings, as well as provide extra stability. Customized versions are also available with the
panel separated from the control unit; contact Tech Support for details.
These Exulus spatial light modulators have input ports compatible with HDMI* connectors and ship with two corresponding cables: one for connecting to an
HDMI-compatible output, and one for connecting to a DisplayPort*-compatible output. Also included are a mini-USB cable for connecting to a PC, a power supply
with a location-specific power cord and a HKTS-5/64 hex key thumbscrew for adjusting the horizontal and vertical tilt adjusters.
High-Power Models
Each high-power SLM (EXULUS-HD2HP and EXULUS-HD3HP) features a liquid-cooled SLM head and adapter board, which can be mounted directly on the
controller or positioned separately from the main housing. The SLM head includes two preinstalled 1/4" hoses with CPC®† valved quick-connect coupling inserts
for easy connection to a chiller, and the adapter board houses the FPC connectors and a circuit board that connects the controller and SLM head. We
recommend using Thorlabs' LK220 chiller (sold below) for full compatibility with the Thorlabs EXULUS software package.
These high-power spatial light modulators have input ports compatible with HDMI* connectors and ship with two corresponding cables: one for connecting to an
HDMI-compatible output, and one for connecting to a DisplayPort*-compatible output. A mini-USB cable is also included for connecting to a PC. To aid in
connecting to a liquid chiller, two CPC valved quick-connection fittings for both 4.3 mm (0.17") and 6.0 mm (0.24") inner diameter hoses are included with the
unit, as well a 2.5 mm stereo cable for thermistor compatibility. A power supply with a location-specific power cord, a USB drive with the software and manual,
and a BD-2M 2 mm balldriver for removing the adapter board and SLM head from the main unit are also shipped with these Exulus models.
*HDMI is a trademark or registered trademark of HDMI Licensing Administrator, Inc. DisplayPort is a trademark owned by the Video Electronics Standards
Association (VESA) in the United States and other countries. The use of such trademarks by Thorlabs does not constitute or imply any affiliation with or
endorsement or sponsorship by their respective trademark owners.
†CPC® is a registered trademark of Colder Products Company.
a.
Angles of incidence other than 0° will result in phase shifts that differ from the programmed pattern. Angles of up to 10° are possible without significantly
affecting performance.
Frame Boost Mode (referred to as Triple Mode in the software) plays the R, G, and B channels of the video signal in succession, for an overall frame rate
of 180 Hz.
These retardance ranges are achievable by setting the phase stroke mode to half wave or full wave in the software.
HD2HP and HD3HP phase/retardance range values are for 30 °C when used with the LK220 liquid chiller.
Item # EXULUS-HD1(/M)
Panel Resolution 1920 x 1080 (Full HD)
Type Liquid Crystal on Silicon (LCoS) with Reflective Coating
Operating Wavelength 400 - 850 nm
Panel Active Area 12.5 mm x 7.1 mm
Pixel Pitch 6.4 µm
Fill Factor >93%
Reflective Coating Aluminum
Average Reflectance 75% (Typical)
Phase / Retardance Range 2π at 633 nm (Standard Mode); 4.7π at 532 nm (Extended Mode)
Angle of Incidencea0°
Optic Axis 45°
Reflected Wavefront Distortion <λ/7 @ 633 nm
Damage Threshold
CWb5 W/cm (532 nm, Ø0.0107 mm)
Pulsed (ns) 0.63 J/cm2 (532 nm, 8.6 ns, 10 Hz, Ø203 µm)
Pulsed (fs) 0.138 J/cm2 (535 nm, 59.4 fs, 100 Hz, Ø188 µm)
Frame Rate 60 Hz (Standard Mode); 180 Hz (Frame Boost/Triplec)
Fluctuation / Flickering (RMS)d<1% (Standard Mode); <5% (Extended Mode)
Beam Deviation Using Panel Tip / Tilt ±3.2°
Trigger OutputeNone
Trigger Output High Voltage Level N/A
Trigger Output Pulse Width N/A
Dimensions (L x W x H)f172.0 mm x 110.0 mm x 81.6 mm (6.77" x 4.33" x 3.21")
Weight 1.24 kg (2.73 lbs)
Storage Temperature 0 °C to 60 °C (32 °F to 140 °F)
Operating Temperatureg10 °C to 40 °C (50 °F to 104 °F)
PC Connection HDMI-Compatible Connector
USB 2.0 Connector
Bit Depth 8 Bit, 0 - 255 Gray Level
Other angles of incidence will result in phase shifts that differ from the programmed pattern. Angles of
up to 10° are possible without significantly affecting performance.
The power density of your beam should be calculated in terms of W/cm. For an explanation of why the
linear power density provides the best metric for long pulse and CW sources, please see the Damage
Thresholds tab.
Frame Boost Mode (referred to as Triple Mode in the software) plays the R,G, and B channels of the
video signal in succession, for an overall frame rate of 180 Hz.
Fluctuation / Flickering is the phase fluctuation as the percentage of the entire phase range and is
dependent on current phase setting. The value stated is the maximum fluctuation and typically occurs at
half of the phase range.
For more details on the external trigger output, please refer to the product manuals accessible through
the red Docs ( ) icons below.
The reported height dimension includes the maximum travel range of the adjuster knob.
SPECS
c.
b.
d.
e.
a.
b.
c.
d.
e.
f.
Ambient temperature fluctuations may cause the characteristics of your SLM to change. Using it at an
ambient temperature of 25 °C is recommended.
Item # EXULUS-HD2 EXULUS-HD3 EXULUS-HD4
Panel Resolution 1920 x 1200 (WUXGA)
Type Liquid Crystal on Silicon (LCoS) with Reflective Coating
Operating Wavelength 400 - 850 nm 650 - 1100 nm 1550 nm
Panel Active Area 15.42 mm x 9.66 mm
Pixel Pitch 8 µm
Fill Factor >92%
Reflective Coating Aluminum Dielectric
Average Reflectance 80% (Typical) 82% (Typical)
Phase / Retardance Range 2π at 633 nm (Full Wave Mode)
π at 633 nm (Half Wave Mode)
2π at 1064 nm (Full Wave Mode)
π at 1064 nm (Half Wave Mode)
2π at 1550 nm (Full Wave Mode)
π at 1550 nm (Half Wave Mode)
Angle of Incidencea0°
Optic Axis 0°
Reflected Wavefront Distortion <λ/2 @ 633 nm <0.4λ @ 633 nm
Damage Threshold
Pulsed (ns) 0.22 J/cm2
(532 nm, 6.8 ns, 10 Hz, Ø200.5 µm)
0.15 J/cm2
(1064 nm, 10 ns, 100 Hz, Ø235 µm)
0.187 J/cm2
(1550 nm, 6.0 ns, 10 Hz, Ø230.6 µm)
Pulsed (fs) 0.0935 J/cm2
(515 nm, 203.3 fs, 100 Hz, Ø108.2 µm)
0.03 J/cm2
(1030 nm, 200 fs, 100 Hz, Ø135 µm)
0.076 J/cm2
(1550 nm, 55.6 fs, 100 Hz, Ø143.1 µm)
Frame Rate 60 Hz
Fluctuation / Flickering (RMS)b<0.01% <0.05% <0.15%
Beam Deviation Using Panel Tip / Tilt ±3.2°
Trigger OutputcSMA Female
Trigger Output High Voltage Level 5 V (TTL)
Trigger Output Pulse Width 54 µs
Dimensions (L x W x H)d155.9 mm x 104.3 mm x 42.0 mm (6.14" x 4.11" x 1.65")
Weight 0.76 kg (1.68 lbs)
Storage Temperature 0 °C to 60 °C (32 °F to 140 °F)
Operating Temperaturee10 °C to 40 °C (50 °F to 104 °F)
PC Connection HDMI-Compatible Connector
USB 2.0 Connector
Bit Depth 8 Bit, 0 - 255 Gray Level
Other angles of incidence will result in phase shifts that differ from the programmed pattern. Angles of up to 10° are possible without significantly
affecting performance.
Fluctuation / Flickering is the phase fluctuation as the percentage of the entire phase range and is dependent on current phase setting. The value stated
is the maximum fluctuation and typically occurs at half of the phase range.
For more details on the external trigger output, please refer to the product manuals accessible through the red Docs ( ) icons below.
The reported length dimension includes the maximum travel range of the adjuster knob. The specified height does not include the dust cover; when
included, this dimension is nominally 46 mm.
Ambient temperature fluctuations may cause the characteristics of your SLM to change. Using it at an ambient temperature of 25 °C is recommended.
Item # EXULUS-HD2HP EXULUS-HD3HP
Panel Resolution 1920 x 1200 (WUXGA)
Type Liquid Crystal on Silicon (LCoS) with Reflective Coating
Operating Wavelength 400 - 850 nm 650 - 1100 nm
Panel Active Area 15.42 mm x 9.66 mm
Pixel Pitch 8 µm
Fill Factor >92%
Reflective Coating Aluminum
g.
a.
b.
c.
d.
e.
Average Reflectance 80% (Typical)
Phase / Retardance Rangea2π at 633 nm (Full Wave Mode)
π at 633 nm (Half Wave Mode)
2π at 1064 nm (Full Wave Mode)
π at 1064 nm (Half Wave Mode)
Angle of Incidenceb0°
Optic Axis 0°
Reflected Wavefront Distortion <λ/2 @ 633 nm <0.4λ @ 633 nm
Frame Rate 60 Hz
Optical Power Handlingc≤200 W/cm
Damage Threshold
Pulsed (ns) 0.22 J/cm2
(532 nm, 6.8 ns, 10 Hz, Ø200.5 µm)
0.15 J/cm2
(1064 nm, 10 ns, 100 Hz, Ø235
µm)
Pulsed (fs)
0.0935 J/cm2
(515 nm, 203.3 ns, 100 Hz, Ø108.2
µm)
0.03 J/cm2
(1030 nm, 200 fs, 100 Hz, Ø135
µm)
Fluctuation / Flickering (RMS)d<0.01% <0.15%
Beam Deviation Using Panel Tip /
Tilt N/A
Trigger OutputeSMA Female
Trigger Output High Voltage
Level 5 V (TTL)
Trigger Output Pulse Width 54 µs
Connector Type (for Tubing) CPC® Valved Thumb Latch Quick-Disconnect Fitting
Tubing Dimensions 0.17" (4.3 mm) Inner Diameter (Pre-Installed)
0.24" (6 mm) Inner Diameter (Optional)
Dimensions (L x W x H)
220.0 mm x 104.0 mm x 68.0 mm (8.66" x 4.09" x 2.68") All-in-One Mode
420.0 mm x 104.0 mm x 42.0 mm (16.54" x 4.09" x 1.65") Separate-
Panel Mode
Weight 0.7 kg (1.54 lbs)
Storage Temperature 0 °C to 60 °C (32 °F to 140 °F)
Operating Temperaturee10 °C to 40 °C (50 °F to 104 °F)
PC Connection HDMI-Compatible Connector
USB 2.0 Connector
Bit Depth 8 Bit, 0 - 255 Gray Level
SLM Head Thermistor
Type VISHAY NTC LE413 (R0 = 10 kΩ @ T0 = 25 °C, B = 3435 K)
Accuracy ±0.5 °C (@ 25 °C)
Phase/retardance range values are for 30 °C when used with the LK220 liquid chiller.
Other angles of incidence will result in phase shifts that differ from the programmed pattern. Angles of
up to 10° are possible without significantly affecting performance.
Specification with the LK220 Liquid Chiller
Fluctuation / Flickering is the phase fluctuation as the percentage of the entire phase range and is
dependent on current phase setting. The value stated is the maximum fluctuation and typically occurs at
half of the phase range.
For more details on the external trigger output, please refer to the product manuals accessible through
the red Docs ( ) icons below.
Ambient temperature fluctuations may cause the characteristics of your SLM to change. Using it at an
ambient temperature of 25 °C is recommended.
Diffraction Efficiency
DIFFRACTION EFFICIENCY
a.
b.
c.
d.
e.
f.
Phase Patterns Used to Measure Diffraction Efficiency
Click to Enlarge Click to Enlarge
Click to Enlarge Click to Enlarge
When a repeating, linear phase pattern is displayed on the SLM, it will function similarly to a blazed diffraction grating. The diffraction efficiency is the power in
the first-order of the diffraction pattern divided by the zero-order when the phase of the SLM is set to zero across the panel. These measurements were made at
633 nm, 1064 nm, or 1550 nm for several test patterns with varying phase steps, effectively creating gratings with varying line spacing (denoted as line pair
/ mm). The measured results and patterns used are plotted below.
Click to Enlarge
Frame Tab in Standard Frame Rate Mode:
Setting a specific gray level from 0 to 255 will set
the entire panel to a certain phase level.
"Spatial Light Modulator" Software Package for EXULUS-HD1
Each Exulus® SLM comes with a software interface that provides complete control of the SLM panel as well as
device settings. Users can input a specific phase level (gray level) over the entire panel, import a custom image,
produce a computer generated holography (CGH) pattern, and other patterns such as Fresnel lenses and
diffraction gratings. All the patterns can be saved into a sequence list and played with a predefined interval of
16.7 ms (60 Hz frame rate, EXULUS-HD1, EXULUS-HD2, EXULUS-HD3, EXULUS-HD4, EXULUS-HD2HP, and
EXULUS-HD3HP). The EXULUS-HD1 also features a triple mode; if RGB images are used then the RGB channels
will be played in succession for an overall frame rate of 180 Hz. The software also supports video input at 1080p or
4K resolution with the H.264 video codec (supported file formats: MP4, M4V, and MOV).
Note: There are two separate software packages for our Exulus spatial light modulators:
The "Spatial Light Modulator" software package is designed for use with our EXULUS-HD1.
The "Thorlabs EXULUS" software package is designed for use with our EXULUS-HD2, EXULUS-HD3,
EXULUS-HD4, EXULUS-HD2HP, and EXULUS-HD3HP SLMs.
Click the yellow bars below for screenshots highlighting various software features and capabilities:
SOFTWARE
Software
"Spatial Light Modulator" Software
Version 1.0.12
This software package is designed for use
with our EXULUS-HD1 SLMs.
"Thorlabs EXULUS" Software Version
2.5.1
This software package is designed for use
with our EXULUS-HD2, EXULUS-HD3,
EXULUS-HD4, EXULUS-HD2HP, and
EXULUS-HD3HP SLMs.
Click the button below to visit the software
page.
Click to Enlarge
Frame Tab in Triple Frame Rate Mode (EXULUS-HD1):
Each of three successive frames (at 180 fps) can have a
different gray level.
Click to Enlarge
File Tab: Upload a user-defined pattern in PNG,
JPEG, or BMP format.
Click to Enlarge
CGH Tab: Convert a user-defined image into a
holographic pattern. For more details, please see
the
App Note
tab.
Click to Enlarge
Pattern Tab for Fresnel Lens Generation: Sets
the SLM panel to focus the reflected light at a
user-selected wavelength and focal length.
Click to Enlarge
Pattern Tab for Diffraction Grating Generation:
Sets the SLM panel to diffract the reflected light with
user-selected wavelength, deviation angle, and
grating rotation angle. For more infromation about
the diffraction efficiency of different patterns, please
see the
Specs
tab.
Click to Enlarge
Video Tab: User-uploaded video can be played on
the SLM panel. In standard mode, grayscale video
can be played at a 60 Hz (EXULUS-HD1, EXULUS-
HD2, and EXULUS-HD4) frame rate. In triple mode
(EXULUS-HD1 only), a color video will play the R,
G, B channels in succession at a 180 Hz frame
rate.
Click to Enlarge
Frame Tab in Standard Frame Rate Mode:
Click to Enlarge
File Tab: Upload a user-defined pattern in PNG,
"Thorlabs EXULUS" Software Package for EXULUS-HD2, EXULUS-HD3, EXULUS-HD4,
EXULUS-HD2HP, and EXULUS-HD3HP
Setting a specific gray level from 0 to 255 will set
the entire panel to a certain phase level.
JPEG, or BMP format.
Click to Enlarge
CGH Tab: Convert a user-defined image into a
holographic pattern. For more details, please see
the
App Note
tab.
Click to Enlarge
Pattern Tab for Fresnel Lens Generation: Sets
the SLM panel to focus the reflected light at a
user-selected wavelength and focal length.
Click to Enlarge
Pattern Tab for Diffraction Grating Generation:
Sets the SLM panel to diffract the reflected light with
user-selected wavelength, deviation angle, and
grating rotation angle. For more infromation about
the diffraction efficiency of different patterns, please
see the
Diffraction Efficiency
tab.
Click to Enlarge
Pattern Tab for Vortex Generation: This
pattern creates a helical output beam and contains
a characteristic donut beam profile. The mode
contains two parameters: wavelength and pattern
order m.
Click to Enlarge
Pattern Tab for Cubic Phase Generation: This
pattern generates a non-diffracted beam with self-
recovery characteristics, commonly called an airy
beam. The mode contains two parameters:
wavelength and alpha.
Click to Enlarge
Sensor Setting: When a high-power SLM is
connected to the LK220 chiller, the temperature
sensor can be set to internal or external mode. The
internal sensor measures the output coolant
temperature, while the external sensor gives the
thermistor temperature reading from the LK220
chiller.
Polarization Dependence of Phase-Only Spatial Light
Modulators (SLMs)
The optical working principles of liquid crystal on silicon SLMs that
provide phase-modulated output beams are illustrated.
Click to Enlarge
Figure 1: A schematic diagram of the SLM LCoS
panel.
Overview
Two-
dimensional
spatial light
modulators
(SLMs) offer
individually
addressable
pixels of phase
shift. Thorlabs' Exulus® 2D SLM is fabricated with liquid crystal on silicon (LCoS) technology, which is based on display technology. This allows it to provide far
more pixels than lower-order phase modulators such as segmented or deformable mirrors. Also, the phase shift of one pixel has little crosstalk with other pixels.
Therefore, the Exulus 2D SLM is perfect for many beam manipulation applications including optical trapping, beam steering and shaping, femtosecond pulse
shaping, adaptive optics, imaging applications, and holography.
APP NOTE
Click to Enlarge
Figure 2: Setup for CGH using the EXULUS-HD1 SLM. In this case, the
focusing effect added to the CGH is set to a 100 000 mm focal length.
[APPLIST] [APPLIST]
These product lists do not include the optical breadboard, laptop, or
screws used to mount the post holders to the breadboard.
Click to Enlarge
Figure 4: CGH projection of an image using the setup
shown in Figure 2 and the image shown in Figure 3.
The central bright spot is a zero-order diffraction spot
due to the gaps between the SLM pixels.
Click for Full-Resolution Example Image
a.
Click to Enlarge
b.
c.
Figure 3: a. The image used to generate the holographic projection.
b. The corresponding CGH pattern generated by the Exulus software.
The main component of the Exulus® is the 2D SLM LCoS panel. Figure 1 shows a basic schematic of the LCoS panel. The liquid crystal layer is sandwiched
between the top transparent and conductive ITO electrode, and the reflective electrode on the bottom. Each pixel on the SLM panel corresponds to individually
addressable electrodes on the bottom. Together with the ITO layer on top, an electric field is built up by applying a voltage between the two electrodes. The liquid
crystal modules line up according to the direction and strength of the electric field. Since liquid crystal is a birefringent material, the alignment of the liquid crystal
molecules in turn controls the retardance or phase shift of each pixel. A wavefront that is incident on the panel reflects with its phase or wavefront being shifted
according to the signal that is sent to the SLM panel. With a properly calculated pattern on the SLM panel, the reflected wavefront results in different optical
effects in the far field. These effects typically include diffraction, tilt, focus, and holographic image formation.
Holographic Projection
We show here a holographic projection as one of the applications of the Exulus SLM.
Figure 2 shows a typical setup required to realize a 2D holographic projection using the
EXULUS-HD1. A collimated laser beam is incident on the SLM panel; best results for
holographic projection are obtained using a beam size just smaller than Ø7 mm. The
incident beam passes through a polarizer and a half-wave plate such that it is polarized
at 45°, the direction of the optical axis of the panel. The target projection image is first
converted into a computer generated holography (CGH) pattern that is calculated by
the bundled software (accessed through the CGH tab in the software). The output
beam is separated from the incident beam with a beam splitter. Within the SLM
software, a focusing effect is added to the CGH pattern; if you do not desire to have
the SLM provide focusing, set the focal length to an extremely long value. In this
example, we have set the focal length to 100 000 mm (at the laser wavelength of 635 nm), checked the "Invert Image" box to set the image outline to be bright in
the projected pattern, and set the position to "Fit" so that the entire image is visible on the preview. Since CGH relies on far-field diffraction, a set of imaging
lenses is required to produce a sharp holographic image on a screen (in this example, first lens: f = 50 mm, second lens: f = 75 mm). Figure 3 shows the
holographic image to be projected and the corresponding CGH pattern, which is calculated using the bundled software. The resulting holographic projection is
shown in Figure 4.
c. The CGH settings tab in the Exulus software.
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Otros manuales de Modulador de THORLABS
