In the triple pass
AOTF arrangement the selected beam is diffracted three times by the sound wave in the crystal, and as such improves the suppression of unwanted spectral parts of the supercontinuum source (white light laser).
The remote monitor is comprised of a C|O.sub.2~ laser, a nonlinear crystal, optics, an AOTF, detectors and a computer, as shown in Figure 1.
The receiver optics collects the reflected beam with a 30 cm mirror and focuses it through the AOTF onto the detectors.
The AOTF directs the received radiation to the two detectors by using one transducer for the 7 to 14 |micro|meter~~ portion and a second transducer for the 3.5 to 7 |micro|meter~~ portion.
Foss and Thermo Mattson are among a number of dispersive NIR vendors, while Brimrose offers
AOTF NIR systems.
The Model LSI-NIR-VT Near-Infrared Vector Probe fiber optic device is designed for diffuse reflectance spectroscopy and interfaces with most existing FIIR,
AOTF, and dispersive spectrometers, requiring high sensitivity and dynamic range.
It is composed of an acoustooptic tunable filter (
AOTF) for wavelength distinction an avalanche photodiode (APD) for detector, a fiberoptic probe, holographic notch filters for Rayleigh injection, and a diode laser for excitation.