Tunable external-cavity diode laser at 650 nm based on a transmission diffraction grating

Area of Science:

• Optics and Photonics
• Laser Technology

Background:

• External-cavity diode lasers (ECDLs) are crucial for applications requiring tunable, single-mode laser sources.
• Traditional ECDL designs often face challenges in achieving broad tunability and stable single-mode operation.

Purpose of the Study:

• To develop and characterize a novel tunable external-cavity diode laser (ECDL) system.
• To utilize a transmission diffraction grating in a Littrow mount for precise wavelength selection.

Main Methods:

• A single-transverse-mode diode laser operating at 650 nm was integrated into an external-cavity configuration.
• A transmission diffraction grating, fabricated using electron-beam lithography, served as the dispersive element.
• The laser system was characterized for output power, wavelength tuning range, and mode-hop-free tunability.

Main Results:

• A tunable, true single-mode continuous-wave (cw) output power exceeding 20 mW was achieved.
• The ECDL demonstrated a total wavelength tuning range of 12 nm.
• A mode-hop-free continuous tunability range greater than 20 GHz was successfully obtained.

Conclusions:

• The developed ECDL, incorporating a Littrow-mounted transmission diffraction grating, provides a robust platform for tunable, single-mode laser emission.
• The system's performance metrics indicate its suitability for applications demanding precise wavelength control and stability.
• Electron-beam lithography enabled the fabrication of a high-performance diffraction grating for enhanced laser tunability.