Pressurized semiconductor membrane becomes widely tunable light emitter

Dec. 1, 2018
An indium gallium nitride membrane, when pressurized like a balloon, shifts its near-IR output wavelength by more than 250 nm and could lead to similar widely tunable lasers.

There is more than one way to create a tunable laser. The first, which is commonly used, is to introduce a spectrally selective optical element into the laser system that can be tuned to pick out a subset of the laser’s entire gain spectrum. The second is to actually alter the spectral position of the laser gain output—for example, by changing the temperature of the laser gain material or by mechanically straining the gain medium. An innovative way to achieve the latter approach has been developed by researchers at Boston University (Boston, MA), the University of Wisconsin-Madison, and Sandia National Laboratories (Albuquerque, NM). Starting with a single-crystal semiconductor membrane, the researchers stretch the membrane by pressurizing it. Using an indium gallium arsenide (InGaAs) membrane as a light emitter (though, at least in this experiment, not as a laser), the researchers could shift the bandgap energy, and thus the photoluminescence (PL) center wavelength, by more than 250 nm in the near-infrared.

The 5 × 5 mm, 100-nm-thick (001) In0.53Ga0.47As film, which is anneal-bonded to a 125-μm-thick flexible film of Kapton polyimide, is mounted to a rigid cell that can be pressurized with gas. Various pressures ranging from 0 to 620 kPa over ambient pressure are applied, producing a strain of up to 1.1%. The membrane is optically pumped by a tunable optical parametric oscillator (OPO) supplying pulses at a 1100 nm wavelength, 5 ns duration, 20 Hz repetition rate, and 0.5 mW average power, focused to a spot size on the membrane of about 1 mm. Measurements with a room-temperature extended-range InGaAs photodetector show a red shift as the pressure increases, as well as some broadening of the PL bandwidth. Future versions, more easily tunable using piezo or MEMS actuators, could form the basis for widely tunable semiconductor lasers. X. Wang et al., Appl. Phys. Lett. (2018); https://doi.org/10.1063/1.5055869.

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

Sponsored Recommendations

How Precision Motion Systems are Shaping the Future of Semiconductor Manufacturing

March 28, 2024
This article highlights the pivotal role precision motion systems play in supporting the latest semiconductor manufacturing trends.

Understanding 3D Printing Tolerances: A Guide to Achieving Precision in Additive Manufacturing

March 28, 2024
In the world of additive manufacturing, precision is paramount. One crucial aspect of ensuring precision in 3D printing is understanding tolerances. In this article, we’ll explore...

Automation Technologies to Scale PIC Testing from Lab to Fab

March 28, 2024
This webinar will cover the basics of precision motion systems for PIC testing and discuss the ways motion solutions can be specifically designed to address the production-scale...

Case Study: Medical Tube Laser Processing

March 28, 2024
To enhance their cardiovascular stent’s precision, optimize throughput and elevate part quality, a renowned manufacturer of medical products embarked on a mission to fabricate...

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!