Microsystem-based External Cavity Diode Laser
External cavity diode lasers with narrow band emission in the red spectral range are developed and used as excitation light sources for Raman spectroscopy. These compact devices are realized using microoptical components and enable portable Raman-measurement systems for the application in biology, medicine, and pharmacy. Currently, these diode lasers are used for in situ characterization of meat quality.
Moreover, this concept has been extended, and diode lasers are realized for Shifted Excitation Raman Difference Spectroscopy (SERDS).
A broad area or tapered laser diode is mounted on a micro-optical bench. The rear facet of this device is anti-reflection coated. On the back side microptics direct the beam to a reflecting Bragg grating (RBG). This RBG stabilizes the emission wavelength and its spectral width of typically 100 pm.
- Excitation light source for Raman spectroscopy and Shifted Excitation Raman Difference Spectroscopy (SERDS)
- Pump source for the non-linear frequency conversion
- 671 nm
- 785 nm
Technology and Mounting
- Semiconductor structures with MOVPE
- Broad area and tapered diode lasers with anti reflection coated rear facets
- Active alignments on a micro-optical bench
These diode lasers were developed in the BMBF project FreshScan supported by the project executing agency VDI/VDE Innovation + Technik GmbH (funding period: 01.07.2006 - 31.12.2009).