Multi-Wavelength External Cavity Lasers for Fluorescence-Free Raman Spectrometers

Abstract

The invention discloses a multi-wavelength external cavity laser for a non-fluorescence raman spectrometer. More than two laser diodes with equal central wavelengths in an array are driven to be independently opened and closed through a power supply switching circuit; output light beams are calibrated into parallel collimated laser beams through a collimating laser calibration optical element; a special design is adopted by a grating; different grating periods are set for incident point regions, corresponding to the collimated laser beams, of the grating; the collimated laser beams form zero-order reflected beams and first-order diffracted beams after being diffracted by the grating; the zero-order reflected beams are output in the same direction and have a wavelength difference; the first-order diffracted beams return to the inside of the corresponding laser diodes along the original path to participate in internal mode competition of a resonant cavity; and the zero-order reflected beams are converged into an optical fiber combiner through an optical fiber coupling lens for wavelength output. The wavelength output is switched by the circuit, so that the unreliability and the possible error of conventional mechanical adjustment are eliminated; a tuning structure is relatively simple and stable; high stability of output wavelengths is ensured; the wavelength output repeatability in actual operation is high; and the tuning accuracy is relatively high.

Description

technical field [0001] The invention relates to an external cavity laser emitting device, in particular to a multi-wavelength external cavity laser used for a non-fluorescent Raman spectrometer. Background technique [0002] At present, Raman spectroscopy is widely used in field detection, drug analysis, pesticide detection and other fields. However, in the process of detecting pesticides, drugs, explosives, etc., Raman spectra are interfered by strong fluorescence. The Raman light intensity is so much smaller than the fluorescence intensity that it is overwhelmed by the fluorescence and cannot detect the Raman spectrum. Therefore, it is necessary to suppress fluorescence in order to efficiently detect Raman spectrum. [0003] At this stage, there are many methods to suppress fluorescence, the main method is baseline correction. Baseline correction is to fit the fluorescent background in the spectrogram through a specific algorithm and subtract it. Due to fitting errors,...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a multi-wavelength external cavity laser for a non-fluorescent Raman spectrometer, which is based on the principle of frequency shift excitation, and can overcome the complex tuning structure of known laser emitting devices, poor stability, weak output wavelength repeatability, multiple The shortcomings of wavelength switching and adjustment are inconvenient, aiming to achieve a stable structure without grating moving parts, more convenient operation, more stable output wavelength, and easy coupling

Images