High current short pulse driver using a high power diode laser for optoacoustic biomedical imaging techniques

Area of Science:

• Biomedical Imaging
• Optoacoustics
• Laser Technology

Background:

• Optoacoustic imaging merges ultrasound's spatial resolution with optical spectroscopy's specificity.
• Solid-state lasers are common light sources but are bulky and slow.
• High Power Diode Lasers (HPDLs) offer a compact, faster alternative but have lower peak power.

Purpose of the Study:

• To design and test a pulsed diode laser driver for enhanced optoacoustic imaging.
• To optimize current pulses for maximizing optical peak power from HPDLs.
• To investigate HPDL operation beyond standard ratings for improved performance.

Main Methods:

• Developed a pulsed diode laser driver using RF power MOSFETs.
• Optimized current pulse parameters (e.g., >900 A, 50 ns duration).
• Tested a low-cost HPDL beyond datasheet specifications (high current, short pulse duration).

Main Results:

• Achieved current pulses exceeding 900 A with 50 ns duration.
• Operated HPDL at >250 A and <60 ns pulse duration without degradation.
• Obtained 750 W peak optical power and 31.2 µJ pulse energy at 40 ns.
• Demonstrated enhanced optoacoustic images compared to standard operation.

Conclusions:

• The developed driver significantly boosts HPDL performance for optoacoustic imaging.
• Operating HPDLs beyond specifications yields improved imaging quality.
• This approach offers a cost-effective enhancement for optoacoustic biomedical imaging systems.