Terahertz PHASR Scanner with 2 kHz, 100 picosecond Time-Domain Trace Acquisition Rate and an Extended Field-of-View...

Area of Science:

• Terahertz (THz) spectroscopy and imaging
• Advanced optical sampling techniques
• Biomedical instrumentation

Background:

• The initial Portable HAndheld Spectral Reflection (PHASR) Scanner (version 1.0) enabled Terahertz Time-Domain Spectroscopic (THz-TDS) imaging in clinical and industrial settings.
• Limitations in field-of-view and trace acquisition speed hindered widespread adoption.
• The alignment-free telecentric beam steering design, while innovative, required further optimization.

Purpose of the Study:

• To address the limitations of the PHASR Scanner version 1.0.
• To enhance the field-of-view and speed of THz-TDS imaging.
• To improve the system's suitability for real-time clinical applications.

Main Methods:

• Implementation of a heliostat geometry for beam scanning to expand the field-of-view.
• Reconfiguration of the Asynchronous OPtical Sampling (ASOPS) system to Electronically Controlled OPtical Sampling (ECOPS).
• Characterization and correction of non-linear time-axis distortions in the ECOPS electro-mechanical system.

Main Results:

• Achieved a greater than four-fold increase in field-of-view area due to the heliostat geometry.
• Significantly improved acquisition speed and frequency domain performance via ECOPS.
• Developed PHASR Scanner version 2.0 capable of imaging a 40×27 mm² FOV at 2000 traces/second over a 100 ps range.

Conclusions:

• The PHASR Scanner version 2.0 overcomes previous limitations in field-of-view and speed.
• The optimized heliostat and ECOPS systems enable faster, higher-resolution THz-TDS imaging.
• This advancement is a critical step towards real-time clinical translation of THz-TDS technology.