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External cavity diode laser diffraction9/28/2023 ![]() ![]() Inquiries concerning rights for the commercial use of this invention should be addressed to NASA Glenn Research Center, Innovative Partnerships Office, Attn: Steve Fedor, Mail Stop 4–8, 21000 Brookpark Road, Cleveland, Ohio 44135. For further information, access the Technical Support Package (TSP) free on-line at under the Physical Sciences category. It is preferable to make this spacing smaller than the wavelength resolution of tunable filter, so that for the purpose of filtering, the ECDL spectrum can be regarded as continuous. The length of the external cavity (including the mirror radius) determines the longitudinal mode spacing. The zeroth-order output of the diffraction grating is used as the laser output. The wavelength range is determined by the range of angles intercepted by the mirror hence, the wavelength range can be adjusted by moving the mirror to a different position on the diffraction circle. measuring the linewidth and stability of narrow bandwidth interference filter-stabilized external cavity diode lasers. Thus, many wavelength components are simultaneously oscillating in the external cavity. In this configuration, each wavelength component diffracted from the grating is reflected from the mirror back to the point of diffraction. Preferably, the feedback mirror is cylindrical or spherical and is positioned with its center of curvature at the point of diffraction (the intersection of the laser beam with the diffraction grating). Whereas heretofore, a flat feedback mirror would be used to select a single laser output wavelength, in the present case, a curved feedback mirror is used to select multiple wavelengths. The optical configuration of the broadband ECDL (see figure) is based on, but differs from, a standard configuration known in the art as that of the Littman-Metcalf design. A tunable filter - preferably, a monochromator or a spectrometer - is used to select a portion of the output spectrum. For example, the broadband ECDL is easily coupled into multiple-pass optical-path-lengthenhancement cells. Unlike light-emitting diodes, the ECDL offers the greater brightness, simpler fiber coupling, and superior spatial propagation properties of a laser. The broadband ECDL can, therefore, be likened to a light-emitting diode except that the spectrum incorporates the external- cavity mode structure. To be precise, the output of the tunable, broadband ECDL consists of many narrow spectral peaks spaced at narrow wavelength intervals that, taken together, span a broad wavelength band. The Feedback Mirror Is Made Curved (in contradistinction to flat) to make it select a range of wavelengths(in contradistinction to a single wavelength). However, for preparatory spectroscopic surveys, high sensitivity and narrow-band operation are not needed in such cases, the present broadband ECDL offers a simpler, less-expensive, more-compact alternative to a commercial narrowband ECDL. Heretofore, commercially available ECDLs have been designed, in conjunction with sophisticated tuning assemblies, for narrow- band (and, typically, single-frequency) operation, as needed for high sensitivity and high spectral resolution in some gas-detection applications. Glenn Research Center, Cleveland, OhioĪ broadband external-cavity diode laser (ECDL) has been invented for use in spectroscopic surveys preparatory to optical detection of gases. The angular width of the maxima was 0.5 mrad in the p-n junction plane and 0.25 mrad in a plane perpendicular to the junction.John H. Thus, it has been widely used in optical communication, lidar, environmental monitoring, spectral analysis, optical coherence. Phase locking of the output radiation and mode selection were achieved experimentally in an external Talbot cavity, of length L=Zm. The external-cavity diode laser is advantageous in terms of low noise, high side-mode suppression ratio, high temperature stability, simple structure, and low cost, which has been the preferred scheme to realize wide-tuning and narrow-linewidth characteristics. (ORNL), Oak Ridge, TN (United States) Sponsoring Org.: USDOE ORNL Laboratory Directed Research and Development (LDRD) Program Office of Naval Research (ONR) (United States) OSTI Identifier: 1424490 Alternate Identifier(s): OSTI ID: 1548729 Grant/Contract Number: AC05-00OR22725 Resource Type: Accepted Manuscript Journal Name: Optics Communications Additional Journal Information: Journal Volume: 414 Journal ID: ISSN 0030-4018 Publisher: Elsevier Country of Publication: United States Language: English Subject: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS 42 ENGINEERING diode laser arrays laser beam combining laser beam shaping laser resonators ![]() This topology utilizes a low-efficiency diffraction grating to establish a high-finesse external cavity, strong optical feedback, a high polarization discrimination, and a circular TEM00 output mode. Publication Date: Research Org.: Oak Ridge National Lab. In this Letter, we propose and demonstrate an external-cavity diode laser in second-order Littrow configuration. of Mechanical, Aerospace, and Biomedical Engineering of Tennessee, Knoxville, TN (United States). Computational Sciences and Engineering Division Univ. Center for Engineering Science Advanced Research. ![]()
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