Manijeh Razeghi
The compact laser could sense chemicals for a variety of
applications
(August 10, 2015) The
invisible chemicals around and within us can tell many complicated stories. By
sensing them, security agents can uncover explosive threats. By monitoring them
in our breath, doctors can diagnose serious illnesses. And by detecting them on
distant planets, astronomers may find signs of life.
These chemicals sometimes reveal their secrets when probed
with mid-infrared wavelength lasers. Nearly all chemicals, including
explosives, industrial, and pollutants, strongly absorb light in the
mid-infrared wavelength region, which is often called the “fingerprint region”
for chemicals.
But lasers that work within this range have limitations.
Larger, optically pumped lasers are too complex to use out in the field, and
compact, lightweight diode laser sources have a limited spectral range. Now
Manijeh Razeghi and her team at Northwestern University’s Center for Quantum
Devices have used quantum mechanical design, optical engineering, and materials
development to create a custom-tailored, compact laser diode by integrating
multiple wavelength emitters into a single device.