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Construction and Characterization of External Cavity Diode Lasers for Atomic Physics
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Narrow linewidth near-UV InGaN laser diode based on external cavity fiber Bragg grating
Optics Letters
|March 2, 2021
Summary
We developed a highly coherent, single-frequency laser diode emitting near-ultraviolet light at 400 nm. This compact, low-cost device achieves narrow linewidths, enabling advanced interferometric applications.
Area of Science:
- Optics and Photonics
- Semiconductor Lasers
- Materials Science
Background:
- Achieving high coherence in near-ultraviolet (near-UV) laser diodes is challenging.
- Compact and cost-effective laser sources are crucial for various scientific and industrial applications.
Purpose of the Study:
- To develop a single-mode, single-frequency InGaN-based laser diode emitting at 400 nm.
- To demonstrate high coherency and narrow linewidth in a compact laser design.
Main Methods:
- Fabrication of a narrowband fiber Bragg grating in the near-UV region.
- Utilizing self-injection locking of the laser diode with the fiber Bragg grating.
- Characterization of optical properties including side-mode suppression ratio and output power.
- Detailed frequency noise analysis to determine linewidths.
Main Results:
- Successfully realized an InGaN-based laser diode emitting at 400 nm.
- Achieved single-mode and single-frequency operation via self-injection locking.
- Demonstrated a side-mode suppression ratio of 44 dB and milliwatt output power.
- Measured a sub-MHz integrated linewidth and an intrinsic linewidth of 16 kHz.
Conclusions:
- The developed laser diode exhibits high coherency and a narrow linewidth in the near-UV spectrum.
- The compact and low-cost design makes it suitable for applications requiring high resolution.
- Potential applications include interferometry and other precision optical measurements.
