Acousto-Optic Modulators (AOMs) and Q-Switches

Standard Coating Designed for 1064 nm
Up to 85% Loss Modulation
Rise Times as Low as 115 ns Per mm Beam Diameter
High Damage Threshold: >500 MW/cm²

M16080

Conduction-Cooled Acousto-Optic Modulator, 80 MHz

Non-Diffracted Beam Profile of Q30080 Q-Switch

Q47027

Water-Cooled Acousto-Optic Q-Switch, 27.12 MHz

First-Order Diffracted Beam Profile of Q30080 Q-Switch

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Overview
Specs
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Table 1.1 Key Specification Comparison
Item #	M16080	Q30080	Q47027
Device Type	Modulator	Q-Switch	Q-Switch
Material	Crystal Quartz	Crystal Quartz	Fused Silica
Acoustic Mode	Longitudinal	Longitudinal	Shear
Design Wavelength	1064 nm
Transmission	>99%
Damage Threshold	>500 MW/cm²
Loss Modulation	≥85%^a	≥85%^a	≥55%
Max Beam Diameter	2.5 mm	1.0 mm	4.0 mm
RF Frequency	80 MHz	80 MHz	27.12 MHz
Rise Time	115 ns/mm Beam Diameter	115 ns/mm Beam Diameter	175 ns/mm Beam Diameter
Deflection Angle	15 mrad	15 mrad	7.5 mrad
Cooling	Conduction^b	Conduction^b	Water Cooled^c

With Linear Polarization Perpendicular to Acoustic Propagation
Must Maintain Housing Temperature <50 °C
Must Maintain Water Temperature ≤30 °C, at 0.1 Gallons Per Minute

Applications

High-Speed Laser Power Modulation
Pulse Picking
Active Q-Switching
Frequency Shifting
Intensity Stabilization
Quantum Beamlines
Laser Surface Modification
Laser Marking, Drilling, and Scribing

Features

Compact Acousto-Optic Modulators (AOMs) and Q-Switches for OEM Integration
Acousto-Optic Medium of Fused Silica or Crystal Quartz
High Damage Threshold Coatings: >500 MW/cm²
Conduction-Cooled or Water-Cooled Options
Loss Modulation Up to 85%
RF Drive Frequencies of 27.12 MHz or 80 MHz
>99% Transmission at 1064 nm
Max Beam Diameters from 1.0 mm to 4.0 mm

Contact Us for Your AOM and Q-Switch Applications

Mike DeArmond
Product Line Manager
Office of the CTO

If you have a custom or OEM project, we invite you to contact us to discuss how our engineering expertise and manufacturing capabilities can help you achieve your goals.

We look forward to hearing from you!

Thorlabs' Acousto-Optic Modulator (AOM) and Q-Switches are compact, acousto-optic devices in OEM packaging. These devices utilize the acousto-optic effect to diffract a portion of incident light at a deflection angle. They are useful for applications that require high speed modulation of light in an optical system. Each device is either mounted to a solid aluminum housing to conductively cool the device or utilizes water cooling for applications that generate more heat.

Acousto-optic modulators and Q-switches are variations of acousto-optic devices, designed to direct a portion of input power into a diffracted beam at a deflection angle from the optical axis. The devices use a crystal or glass contacted with a transducer. The transducer is driven with an RF electrical input, generating an acoustic wave that propagates through the material either perpendicular the direction of beam propagation (longitudinal or compression wave) or parallel to beam propagation (shear wave). The optical beam interacts with the acoustic wave, diffracting the beam at an angle from the optical axis. By controlling the power applied to the transducer, the diffraction efficiency can be modulated. Acousto-optic modulators are designed to enable the use of the modulated first order diffracted beam, while acousto-optic Q-switches are AOMs that are used with a laser cavity to bleed off optical power.

Each device is constructed with high damage threshold crystal quartz or fused silica glass. Thorlabs' active acousto-optic modulator (AOM) and Q-switches are prepared with a high-quality anti-reflection (AR) V-coating designed for operation near 1064 nm, to ensure low loss and minimal back reflections from the devices. Key Specifications for each device can be found in Table 1.1, with complete specifications found in the Specs tab.

Acousto-Optic Modulators (AOMs)
AOMs are useful for applications requiring high-speed amplitude modulation. When implemented with appropriate laser power monitoring and feedback electronics, AOMs can be used for power stabilization for applications with stringent power stability requirements, including quantum computing. AOMs are also commonly used in multiphoton microscopy to modulate laser power for deep tissue in-vivo imaging and photo-stimulation.

Acousto-Optic Q-Switches
An acousto-optic Q-switch is a form of AOM engineered for the specific application of intracavity Q-switching. In this application, the AOM is able to control the intracavity loss. When the RF drive is applied, a large portion of optical energy is lost into the diffracted beam, and the cavity quality factor (Q) is kept low, suppressing lasing while the population inversion builds up in the gain medium. When the RF drive is reduced, the losses decrease and the cavity Q factor increases dramatically, resulting in a short, intense pulse of laser emission. This type of Q-switching allows for precise electronic control over pulse timing, repetition rate, and energy.

For alternative materials, coatings, or design wavelengths for OEM integration, please reach out using the Contact Us button in the green box.

Item #	M16080	Q30080	Q47027
Device Type	Modulator	Q-Switch	Q-Switch
Material	Crystal Quartz	Crystal Quartz	Fused Silica
Acoustic Mode	Longitudinal	Longitudinal	Shear
Design Wavelength	1064 nm	1064 nm	1064 nm
Damage Threshold	>500 MW/cm²	>500 MW/cm²	>500 MW/cm²
Windows	AR V-Coated	AR V-Coated	AR V-Coated
Input Polarization	Vertical	Vertical	Arbitrary
Static Transmission	≥99%	≥99%	≥99%
Frequency	80 MHz	80 MHz	27.12 MHz
Loss Modulation	≥85%^a	≥85%^a	≥55%
RF Power	20 W	12 W	≤50 W
Max Beam Diameter	2.5 mm	1.0 mm	4.0 mm
Rise Time	115 ns/mm Beam Diameter	115 ns/mm Beam Diameter	175 ns/mm Beam Diameter
Deflection Angle	15 mrad	15 mrad	7.5 mrad
Impedance (Nominal)	50 Ω	50 Ω	50 Ω
Voltage Standing Wave Ratio (VSWR)	≤1.2:1	≤1.2:1	≤1.2:1
Cooling	Conduction^b	Conduction^b	Water Cooled^c

With Linear Polarization Perpendicular to Acoustic Propagation
Must Maintain Housing Temperature <50 °C
At 0.1 Gallons Per Minute, Must Maintain Water Temperature ≤30 °C

$Q-Switch Diffraction Efficiency$
Click to Enlarge
Figure 2.1 The sample diffraction efficiency of a Q30080 Q-switch with respect to RF drive power is shown above.

Click to Enlarge
Figure 2.2 The reflectance of the standard 1064 nm V-Coating used in Thorlabs' AOMs and Q-switches is shown above.

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High Damage Threshold Acousto-Optic Modulator

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Conduction-Cooled Package for OEM Integration
Designed for 80 MHz RF Drive Frequency and 20 W RF Power
AR V-Coated for ≥99% Transmission at 1064 nm
≥85% Loss Modulation

The M16080 Acousto-Optic Modulator (AOM) is a compact, conduction-cooled device designed for integration into custom or OEM systems. An integrated SMA connector allows an 80 MHz RF signal to drive the built in transducer. This modulator is prepared with a high-quality anti-reflection (AR) V-coating for operation near 1064 nm, with ≥99% transmission.

High Damage Threshold Q-Switches

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Conduction-Cooled or Water-Cooled Package for OEM Integration
RF Drive Frequencies of 27.12 MHz or 80 MHz
AR V-Coated for ≥99% Transmission at 1064 nm
Loss Modulation Up to 85%

Thorlabs' High Damage Threshold Q-Switches are compact devices designed for integration into custom or OEM systems. The Q30080 Q-switch utilizes crystal quartz integrated into a conduction-cooled package to excite a longitudinal acoustic mode, while the Q47027 Q-switch uses fused silica integrated into a water-cooled package to excite a shear acoustic mode. These Q-switches are prepared with a high-quality anti-reflection (AR) V-coating for operation near 1064 nm, with ≥99% transmission.

The Q30080 Q-switch has an integrated SMA connector for providing the 80 MHz RF drive frequency, while the Q47027 Q-switch uses a BNC connector to provide the 27.12 MHz RF drive frequency. The Q47027 also includes a thermal interlock which is accessed via an SMC connector for connection to an RF driver. This interlock will open if a failure in the water circulation causes the temperature to rise to 50 °C, and will reset once the temperature has dropped back down to 30 °C.