Orientation-Patterned Gallium Arsenide (OP-GaAs) Frequency Converter Devices
Description
Physical Sciences Inc. (PSI) has developed a wafer-scale process for the production of a nonlinear optical material called orientation-patterned gallium arsenide (OP-GaAs) and is now offering for commercial sale frequency converter devices based on this new, high efficiency material. The material is patterned to facilitate efficient nonlinear optical frequency conversion using the process of quasi-phasematching (QPM). Figure 1 shows example devices (left) and a Nomarski micrograph of a typical crystal cross-section, showing excellent domain quality in 600 micron-thick devices.
 |
 |
| OP-GaAs frequency converter devices |
Typical cross-sections |
Typical Applications
OP-GaAs is particularly well-suited for the production of tunable radiation in two atmospheric transmission windows: the mid-wave infrared (wavelengths between 3 µm and 5 µm) and the long-wave infrared (wavelengths between 8 µm and 12 µm). This tunable radiation can be produced by nonlinear optical processes such as optical parametric oscillation (using a pump laser with a wavelength between 1.5 µm and 2.5 µm) and difference-frequency generation (using pump and signal lasers with wavelengths between 1.5 µm and 4 µm). It is also well-suited for the production of second-harmonic radiation from carbon dioxide lasers with wavelengths near 10 µm. The high nonlinear coefficient of OP-GaAs makes it an ideal material for the frequency conversion of lasers with relatively high average powers (> 1 W) and relatively low peak powers (< 50 kW) such as continuous-wave lasers or high-repetition-rate diode-pumped solid-state lasers. Radiation produced by these processes can be useful for a variety of applications including remote gas sensing, frequency comb spectroscopy, and infrared countermeasures. Figure 2 shows calculated tuning curves for an optical parametric oscillator with a pump wavelength of 2 mm.
 |
|
Calculated tuning curves for an OP-GaAs optical parametric oscillator with a pump wavelength of 2 mm. Two curves are shown, one for a crystal temperature of 50° C and one for a crystal temperature of 150° C. |
Typical Specifications
Typical specifications for the OP-GaAs frequency converters are summarized in Table 1. Custom devices can be fabricated for specific applications.
Table 1. Specifications for OP-GaAs produced at PSI.
|
type of phasematching |
quasi-phasematching (QPM) |
|
thickness of QPM grating |
0.5 – 0.6 mm |
|
length of QPM grating |
1 mm - 40 mm |
|
width of QPM grating |
1 mm – 10 mm |
|
laser damage threshold (10 ns pulses @ 2 µm) |
1 J/cm2 |
|
laser damage threshold (cw @ 10.6 µm) |
> 500 kW/cm2 |
|
QPM period |
> 40 µm |
|
Thermal conductivity |
55 W/m-°K |
|
Absorption @ 10.6 µm |
0.01 cm-1 |
|
dn/dT (ppm/°C) |
20 |
|
effective nonlinear coefficient |
57 pm/V |
|
anti-reflection coatings |
available upon request |
Thermal mounting is recommended and such submounts or active cooling can be provided.
Contact Information
For more information about device requirements for specification applications and to request a quote, please contact:
Dr. Douglas Bamford, Manager of PSI's Non-linear Optical Materials and Applications Area
bamford@psicorp.com
Physical Sciences Inc.
6652 Owens Drive
Pleasanton, CA 94588
Telephone: (925) 743-1110
Fax: (925) 460-0110