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Acousto-Optic Modulators (AOM) | SIMTRUM Photonics Sotre

Free Space Acousto-Optic Modulators (AOM)

Acousto-optic Modulators

An external cavity device that modulates the intensity of the laser

 

Acousto-optic modulators (AOM) are generally used outside the laser cavity to change the intensity of the incoming laser (amplitude-modulated AM). This can be simple ON/OFF modulation for quick switching or variable level modulation to achieve intensity modulation. The modulation mode is determined by the type of RF driver and can be digital (ON/OFF) or analog (sinusoidal, square wave, linear, random…). 

 

Generally, the RF driver of AOM adopts fixed frequency, the key parameter of the AOM is the rise/fall time, which defines the achievable “speed” or amplitude modulation bandwidth of the modulation. The rise/fall time is proportional to the beam diameter inside the modulator. Therefore, the diameter of the incident laser beam must be controlled in order to obtain a fast rise time. The AOM can be used as a shutter (cyclic switch at a set frequency) or as a variable attenuator (dynamically controlling the intensity of the transmitted light). Laser modulation is achieved by controlling the sound wave in the acousto-optic crystal caused by radio frequency.

 

SIMTRUM offers a series of free-space (up to 24 channels in a single channel) and fiber-coupled (bias-preserving and non-bias-preserving) AOM with a frequency range of up to 300 MHz and a rise as low as 6 ns. We provide AOM-matched series of RF drivers you can choose the corresponding RF driver according to the product specification.

Free space AOM

Product Brochure Link: 

 

Related ltems:Fiber-Coupled AOM

 

Applications of AOM

  • Laser light and Intensity modulation
  • Laser radar or laser scanning
  • Laser switch
  • Laser Chopper

Main Product package list

  • AOM
  • RF Driver (Optional)

Advantages of AOM

  • High-Speed Modulation: AOM can achieve extremely high modulation speeds, typically reaching tens of megahertz (MHz) to several gigahertz (GHz).
  • High Stability and Precision: By precisely controlling the frequency and intensity of sound waves, AOM can achieve highly stable and precise beam modulation.
  • Wide Wavelength Range: AOM is suitable for lasers of various wavelengths, from ultraviolet to infrared.
  • No Mechanical Movement: AOM modulates the beam through sound waves, eliminating the need for mechanical components, reducing wear and maintenance requirements.

Product General specifications

Free-Space Acousto-Optic Modulators (AOM)
Interaction Material Crystalline Quartz / Tellurium Dioxide / Germanium
Acoustic Mode Longitudinal
Operating Wavelength 266 nm ~ 10.6 um (Refer to Model Guide)
Polarization Linear, parallel to base
Transmission > 93% ~ 99.6% (Refer to Model Guide)
Active Aperture 0.5 ~ 8.0 mm (Refer to Model Guide)
Center Frequency (Fc) 40.68 ~ 200 MHz (Refer to Model Guide)
RF Bandwidth (RB) 5 ~ 15 MHz
Diffraction Efficiency @RB > 80% ~ 85% (Refer to Model Guide)
RF Power 2 ~ 80 W (Max)
Input Impedance 50Ω Nominal
VSWR @Fc < 1.2:1 / < 3:1
RF Connector SMA-F / BNC-F
Cooling Conduction-cooled / Water-cooled
Shell Material Aluminum alloy 6063
RF Driver  Every AOM has an diver (Refer to driver guide)

 

Model selection guide

Product Code Wavelength  Active Aperture  Operting Frequency Transmission Diffraction Efficiency Optical Material Cooling Bragg Angle Separation angle Rise time /Beam Size
STM0012-QL200-035-266 266 nm 3.5 200 MHz >99% >85% Crystalline quartz Conduction-cooled 4.6 mrad 9.3 mrad 113ns@1mm/ 226ns@2mm/ 339ns@3mm
STM0011-QL110-060-343 343 nm 6.0 mm 110 MHz >99% >85% Crystalline quartz Water-cooled 3.3 mrad 6.6 mrad 113ns@1mm/ 339ns@3mm/ 678ns@6mm
STM0009-QL170-060-355 355 nm 6.0 mm 170 MHz >93% >85% Crystalline quartz Water-cooled 5.3 mrad 10.5 mrad 113ns@1mm/ 339ns@3mm/ 678ns@6mm
STM0006-QL110-030-532 532 nm 3.0 mm 110 MHz >99% >85% Crystalline quartz Conduction-cooled 5.1 mrad 10.2 mrad 113ns@1mm/ 226ns@2mm/ 339ns@3mm
STM0010-TL080-020-450-900 450-900 nm 2.0 mm 80 MHz >95% >85% Tellurium dioxide Conduction-cooled 6 mrad 12.1 mrad 77.5ns@0.5mm/ 155ns@1mm/ 232.5ns@1.5mm
STM0015-QL100-030-800 800 nm 3.0 mm 100 MHz >99.6% >85% Crystalline quartz Conduction-cooled 7.0 mrad 13.9mrad 113ns@1mm / 339ns@3mm
STM0005-TL080-005-1045 1045 nm 0.5 mm 80 MHz >99.6% >85% Tellurium dioxide Conduction-cooled 9.95 mrad 19.9 mrad 15.5ns@0.1mm/ 46.5ns@0.3mm/ 77.5ns@0.5mm
STM0013-GL041-080-9600 9.6 um 8.0 mm 40.68 MHz >93% >80% Germanium Water-cooled 35.5 mrad 71 mrad 118ns@1mm/ 354ns@3mm/ 826ns@7mm
STM0001-GL041-080-10600 10.6 um 8.0 mm 40.68 MHz >93% >80% Germanium Water-cooled 39.2 mrad 78.4 mrad 118ns@1mm/ 354ns@3mm/ 826ns@7mm
STM0017-TL250-003-780-950 780-950 nm  2.5 ×0.32 mm     250 MHz > 97 % > 70 % @ 150 μm  Tellurium dioxide Conduction-cooled 23.8 mrad 47.6 mrad 29ns@150 μm

AOM Customization Options

(We are able to support customization with additional cost, below are our customization capability for AOM product, if you want to customize the AOM for below 3 specification please send requirement to our sales)

Wavelength Active Aperture Frequency
266nm – 10.6um 0.3mm to 10mm 27.12Mhz to 300Mhz

 

Product Size and Appearance Labeling

 

Water Cooled Type AOM Dimension

(Note: this is general reference size, for specific AOM please refer to product brochures)

Conduction Cooling Type AOM Dimension

(Note: this is general reference size, for specific AOM please refer to product brochures)


RF Driver can generate RF signals and control the switch, frequency, power, etc. of the RF signal through external modulation signals. By modulating the RF signal, modulation of the laser ON/OFF, laser power, beam deflection, and other modulation can be achieved. There are various options for RF driver, such as fixed frequency or tunable bandwidth, with RF frequency mainly ranging from 20MHz to 250MHz.

 

RF power ranging from 1W to 150W, trigger frequency ranging from 1Hz to 1MHz, load of 50ohm, available for digital and analog modulation, 24VDC power supply.

SIMTRUM has a professional R & D and production team, the whole process of product independent production, can be customized according to customer needs.

Our driver support both Digital and Analog single, We are able to provide a range of RF driver based on Frequency, Output power and DC input. below are our driver general specification Range, the cost of RF drive was mainly determined by output power.

 

< 20W : Estimate cost ~1100USD
>20-100W : Estimate cost ~1600USD
>100W : Estimate cost ~2000USD

 

General Specification for RF driver
RF frequency 27.12Mhz -300MHz
Output power 1W-150W
DC Power Input 12Vdc or 15Vdc or 24Vdc
Cooling Conduction cooling/ Water Cooling
Operating Model  Support Both Digital & Analog
Rise-time(10%-90%) 20-50ns 
Fall-time(90%-10%) 20-50ns 
Trigger frequency 100kHz   
Trigger delay  50ns
Output impedance  50Ω

 

Water Cooled RF driver

Conduction cooled RF driver

Fin Cooled RF driver

RF Driver Control logic


Working Principle of AOM (Acousto-Optic Modulator)

 

The working principle of an Acousto-Optic Modulator (AOM) is based on the acousto-optic effect, which utilizes changes in the refractive index caused by the propagation of sound waves in an optical medium to modulate a light beam.

Specifically, the AOM modulates the light beam through sound waves (ultrasound) propagating in a material, usually a transparent crystal or glass.

1.Generation of Sound Waves:A radio frequency (RF) signal is applied to a piezoelectric crystal (transducer). Due to the piezoelectric effect, the piezoelectric crystal generates ultrasound. The ultrasound propagates through the acousto-optic medium, forming a series of density variations known as acoustic waves (acoustic grating).

 

2.Refractive Index Change:As the ultrasound propagates through the acousto-optic medium, it causes periodic changes in the medium's refractive index, forming a dynamic grating. This dynamic grating diffracts the passing light beam. 

 

3.Light Beam Modulation:

  • Frequency Modulation: Due to the high frequency of the sound waves (usually in the range of tens to hundreds of megahertz), the frequency of the incident light beam is modulated by the sound wave frequency, causing a shift in the incident light beam's frequency by one sound wave frequency.
  • Intensity Modulation: By adjusting the power of the RF signal, the intensity of the ultrasound can be changed, thus altering the diffraction efficiency of the dynamic grating to achieve modulation of the light beam's intensity.
  • Direction Modulation: The angle of the diffracted beam depends on the frequency of the sound waves and the incident angle of the light beam. The direction of the diffracted beam can be adjusted by changing the frequency of the RF signal.

 

4.Diffracted Beam:When the incident light beam passes through the acousto-optic medium, it is diffracted into multiple orders of beams by the dynamic grating. Typically, the +1 order or -1 order diffracted beam is used, while the intensity of other orders is relatively low and can be neglected.

 

 

Commonly Used Formulas for AOM ( Acousto-Optic Modulator )

  • Diffraction Efficiency Calculation Formula: Where I0th is the output intensity of the 0th order light when the RF is off, and I1st is the output intensity of the 1st order light when the RF is on.

 

  • Insert Loss Calculation Formula:
  • Saturation Power Calculation Formula: Where L is the electrode length, λ is the wavelength, H is the electrode width, M2 is the acousto-optic figure of merit, and K is the conversion loss factor, typically 1.12.

 

  • Rise Time Calculation Formula:

Where T is the optical rise time,D is the distance, and V is the velocity. This formula defines the transmission time of the acoustic wave across the waist of the AO crystal and is used to approximate the optical rise time for a Gaussian beam.

 𝜃𝐵𝑟𝑎𝑔𝑔=𝜆𝑓/2𝑣    𝜃𝑆𝑒𝑝=𝜆𝑓/𝑣    𝜃𝑆𝑒𝑝=2𝜃𝐵𝑟𝑎𝑔𝑔

 

 𝜆=Wavelength,  𝑓=Frequence V=Sound speed in Material


A: What is the damage threshold for AOM?

Q: Usually, the damage threshold of AOM is determined by the coating and crystal material, but the quality of the coating is more critical. So the damage threshold of AOM varies at different wavelengths. For example: 1064nm, nanosecond laser, the damage threshold is 1GW/cm2.

In general, pulse laser has a greater damage risk to the device. If your pulse laser energy is high, please send us the laser specification to verify the damage threshold.

 

A:Comparison table of sound velocity and applicable wavelength range of acousto-optic material.

Q: 

Material Longitudinal Wave Speed (m/s) Shear Wave Speed (m/s) Applicable Wavelength Range
Quartz 5,980 3,760 ~190 nm - 3.5 µm
Germanium 5,400 3,540 ~2 µm - 14 µm
Lithium Niobate (LiNbO3) 7,330 3,970 ~0.4 µm - 5 µm
Barium Titanate (BaTiO3) 6,500 4,200 ~0.4 µm - 5 µm
Potassium Niobate (KNbO3) 7,150 4,220 ~0.4 µm - 5 µm
Tellurium Dioxide (TeO2) 4,260 2,250 ~0.35 µm - 5 µm
Fused Silica 5,970 3,750 ~180 nm - 3.5 µm
Lead Molybdate (PbMoO4) 3,640 1,840 ~0.4 µm - 3.5 µm

 

A:What is the difference between AOM and EOM?

Q: 

Feature AOM EOM
Modulation Mechanism Acousto-optic effect Electro-optic effect
Speed MHz to GHz Up to tens of GHz
Insertion Loss Higher Lower
Efficiency Lower (due to acoustic wave power) Higher (purely electric field-based)
Wavelength Range Wide (UV to IR) Wide (depends on electro-optic material)
Applications Beam deflection, frequency shifting, intensity modulation High-speed phase, frequency, amplitude modulation
Complexity and Cost Simpler, potentially lower cost More complex, potentially higher cost

Sales Guide

If you need our technical team for guidance on product selection or customization, please help to provide below technical information, it helps to speed up the process.

Items Detail Unit Remark
AOM Technical Sales Guide ( Let us know your desired AOM spec.)
Application      
Operating Wavelength   nm  
Separation Angle   mrad  
Operating RF Frequency   MHz  
Diffraction Efficiency   %  
Active Aperture   mm  
AOM RF driver sales Guide      
Trigger Frequency   Hz  
DC Power Supply   V   
Customer Laser feature (you can also let us know your input laser spec.)
Output Mode   /  
Wavelength   nm  
Beam Diameter   mm if Free space
Fiber Type and Size   / if Fiber coupled
Average Laser Power   W  
Laser Repetition Rate   Hz if Pulsed
Pulse Energy   mJ if Pulsed
Pulse Duration   ns if Pulsed
Polarization   /  

 

AOM Customization Options

(We are able to support customization with additional cost, below are our customization capability for AOM product, if you want to customize the AOM for below 3 specification please send requirement to our sales)

Wavelength Active Aperture Frequency
266nm – 10.6um 0.3mm to 10mm 27.12Mhz to 300Mhz

 

 

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Compare Model Drawings & Specs Availability Reference Price
(USD)
STM0012-QL200-035-266
Acousto-Optic Free-space Modulators (AOM), wavelength 266nm, active aperture 3.5mm, operating frequency 200MHz, Transmission >90%, Diffraction Efficiency >85%, Crystalline quartz, conduction-cooled, provide AOM-matched RF driver
6 - 8 Weeks $6507.00
STM0011-QL110-060-343
Acousto-Optic Free-space Modulators (AOM), wavelength 343nm, active aperture 6.0mm, operating frequency 110MHz, Transmission >99%, Diffraction Efficiency >85%, Crystalline quartz, water-cooled, provide AOM-matched RF driver
1- 2 Weeks $2789.00
STM0009-QL170-060-355
Acousto-Optic Free-space Modulators (AOM), wavelength 355nm, active aperture 6.0mm, operating frequency 170MHz, Transmission >93%, Diffraction Efficiency >85%, Crystalline quartz, water-cooled, provide AOM-matched RF driver
6 - 8 Weeks $2975.00
STM0006-QL110-030-532
Acousto-Optic Free-space Modulators (AOM), wavelength 532nm, active aperture 3.0mm, operating frequency 110MHz, Transmission >99%, Diffraction Efficiency >85%, Crystalline quartz, conduction-cooled, provide AOM-matched RF driver
1 - 2 Weeks $2510.00
STM0010-TL080-020-450-900
Acousto-Optic Free-space Modulators (AOM), wavelength 450-900nm, active aperture 2.0mm, operating frequency 80MHz, Transmission >95%, Diffraction Efficiency >85%, Tellurium dioxide, conduction-cooled, provide AOM-matched RF driver
6 - 8 Weeks $4648.00
STM0015-QL100-030-800
Acousto-Optic Free-space Modulators (AOM), wavelength 800nm, active aperture 3.0mm, operating frequency 100MHz, Transmission >99.6%, Diffraction Efficiency >85%, Crystalline quartz, conduction-cooled, provide AOM-matched RF driver
6 - 8 Weeks $3346.00
STM0005-TL080-005-1045
Acousto-Optic Free-space Modulators (AOM), wavelength 1045nm, active aperture 0.5mm, operating frequency 800MHz, Transmission >99.6%, Diffraction Efficiency >85% >85%, Tellurium dioxide, conduction-cooled, provide AOM-matched RF driver
6 - 8 Weeks $2789.00
STM0013-GL041-080-9600
Acousto-Optic Free-space Modulators (AOM), wavelength 9.6um, active aperture 8.0mm, operating frequency 40.68MHz, Transmission >93%, Diffraction Efficiency >80%, Germanium, water-cooled, provide AOM-matched RF driver
1 - 2 Weeks $12642.00
STM0001-GL041-080-10600
Acousto-Optic Free-space Modulators (AOM), wavelength 10.6um, active aperture 8.0mm, operating frequency 40.68MHz, Transmission >93%, Diffraction Efficiency >80%, Germanium, water-cooled, provide AOM-matched RF driver
1 - 2 Weeks $12642.00
STM0012-QL200-060-266
Acousto-Optic Free-space Modulators (AOM), wavelength 266nm, active aperture 6.0 mm, operating frequency 200MHz, Transmission >90%, Diffraction Efficiency >85%, Crystalline quartz, Water-cooled, provide AOM-matched RF driver
6 - 8 Weeks $7437.00
STM0017-TL250-003-780-950
Acousto-Optic Free-space Modulators (AOM), wavelength 780-950 nm, active aperture 2.5x0.32 mm, operating frequency 250MHz, Transmission >97%, Diffraction Efficiency >70 %@150 μm , Tellurium dioxide, Conduction-cooled, provide AOM-matched RF driver
6 - 8 Weeks Request for quote

STM0017-TL250-003-780-950 - Parameter

STM0012-QL200-060-266 - Parameter

STM0001-GL041-080-10600  - Parameter

STM0013-GL041-080-9600 - Parameter

STM0005-TL080-005-1045 - Parameter

STM0015-QL100-030-800 - Parameter

STM0010-TL080-020-450-900 - Parameter

STM0006-QL110-030-532 - Parameter

STM0009-QL170-060-355 - Parameter

STM0011-QL110-060-343 - Parameter

STM0012-QL200-035-266 - Parameter

STM0017-TL250-003-780-950 - Download

STM0012-QL200-060-266 - Download

STM0001-GL041-080-10600  - Download

STM0013-GL041-080-9600 - Download

STM0005-TL080-005-1045 - Download

STM0015-QL100-030-800 - Download

STM0010-TL080-020-450-900 - Download

STM0006-QL110-030-532 - Download

STM0009-QL170-060-355 - Download

STM0011-QL110-060-343 - Download

STM0012-QL200-035-266 - Download

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Compare Model Drawings & Specs Availability Reference Price
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