Hyperspectral lasers for spectroscopic measurements in the near-infrared

This project develops hyperspectral lasers that are built using fiber-optic cavities and broadband semiconductor gain media. These sources are custom designed for high-speed (typically 30 kHz) spectroscopic sensing applications, such as thermometry based on H2O absorption spectroscopy in harsh, combusting environments that are generally not conducive to more conventional thermometry techniques.;Novel time- and frequency-division multiplexed lasers are introduced that either scan continuously over chosen wavelength ranges or switch among discrete wavelengths. One example is a laser that scans through a 0.1-4 nm range centered near 1350 nm every 10 mus; it is an advanced Fourier domain mode locked (FDML) laser that offers ultra low intensity noise and a significantly narrowed spectral linewidth compared to typical FDML performance. Another example is a discrete time-division multiplexed laser that cycles through 19 spectrally narrow wavelengths in a 44-nm-wide spectral band (1333-1377 nm) every 15 mus, where each wavelength can be aligned to a specific absorption feature.;Such engineered lasers are changing the way one looks at solving spectroscopic sensing problems as these sources can be custom designed to address a particular problem instead of making decisions based on the availability of light sources in the marketplace.