Summary
Contrast enhancement results in larger photothermal refraction signals but increases susceptibility to environmental “noise.”
Active feedback-stabilization limits some environmental “noise” in these sensitive apparatuses.
The optical novelty filter is an easy means to enhance contrast and feedback-stabilize.
The optical novelty filter described here:
- is easy to set up and reproduce
- circumvents alignment and pointing errors using a large probe
- produces both magnitude and image signals with large SNR enhancement
- yields real-time visible images of infrared absorption