532-nm-modulated pulse generation based on a time-delay loop and polarization rotation

Area of Science:

• Optics and Photonics
• Laser Technology

Background:

• Intensity modulation of laser pulses is crucial for various applications.
• Existing methods can be complex or expensive.

Purpose of the Study:

• To investigate a simple and low-cost scheme for generating 532 nm modulated pulses.
• To model and experimentally verify the intensity modulation process.

Main Methods:

• Utilized an external cavity with a temporal delay loop and polarization rotation using half-wave plates (HWPs).
• Modeled pulse train waveforms by analyzing polarization changes over multiple round trips.
• Coupled the modulator with a sub-nanosecond 532-nm laser source for experimental verification.

Main Results:

• Successfully generated modulated pulses with various temporal profiles by rotating HWPs.
• Achieved a fundamental modulation frequency of 520 MHz.
• Observed second harmonic frequencies exceeding 1 GHz.

Conclusions:

• The developed scheme offers a simple, low-cost method for laser pulse intensity modulation.
• The technique is suitable for applications such as underwater detection and ranging.