Abstract
We present a novel method for low noise, high-speed, real-time spectroscopy to monitor molecular absorption spectra. The system is based on a rapidly swept, narrowband CW Fourier-domain mode-locked (FDML) laser source for spectral encoding in time and an optically time-multiplexed split-pulse data acquisition system for improved noise performance and sensitivity. An acquisition speed of $100 kHz, a spectral resolution better than 0.1 nm over a wavelength range of $1335--1373 nm and a relative noise level of $5 mOD ($1e absorbance) are achieved. The system is applied for crank-angle-resolved gas thermometry by H2O absorption spectroscopy in an engine motoring at 600 and 900 rpm with a precision of $1 trigger and synchronization jitter in the electronic detection system, and the accuracy of available H2O absorption databases are discussed.
Originalsprache | Englisch |
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Zeitschrift | Opt. Express |
Jahrgang | 15 |
Ausgabenummer | 23 |
Seiten (von - bis) | 15115-15128 |
Seitenumfang | 14 |
DOIs | |
Publikationsstatus | Veröffentlicht - 01.11.2007 |