High-speed thermoreflectance microscopy using charge-coupled device-based Fourier-domain filtering

Area of Science:

• Thermal imaging
• Microscopy techniques
• Materials science

Background:

• Charge-coupled device (CCD) cameras are crucial for high-resolution imaging.
• Thermoreflectance microscopy offers non-contact surface temperature measurements.
• Improving thermal imaging speed is essential for dynamic thermal analysis.

Purpose of the Study:

• To develop a faster Fourier-domain filtering method for CCD-based thermoreflectance microscopy.
• To maintain high thermal sensitivity while increasing imaging speed.
• To compare the proposed method with the conventional four-bucket technique.

Main Methods:

• Utilized fast Fourier transform (FFT) to convert time-varying reflected light data to the frequency domain.
• Applied frequency peak filtering followed by inverse FFT to obtain thermoreflectance images.
• Recorded reflected light distribution from a bias-modulated microresistor surface using a CCD camera.

Main Results:

• The Fourier-domain filtering method achieved 24-42 times faster thermal imaging compared to the four-bucket method.
• High thermal sensitivity was maintained with the proposed method.
• Quantitative comparison validated the speed enhancement.

Conclusions:

• The proposed Fourier-domain filtering method significantly accelerates CCD-based thermoreflectance microscopy.
• This advancement enables faster dynamic thermal analysis with high sensitivity.
• The method offers a substantial improvement over conventional techniques for thermal imaging.