Fluorescence-detected mid-infrared photothermal microscopy

A fluorescence-detected mid-infrared photothermal microscopy system capable of discriminating between two components in a sample, comprising:

• a multichannel laser array configured to energize a sample with one or more modulated infrared (IR) beams;
• a continuous laser source configured to provide concurrent and continuous illumination of the sample with a probe beam, thereby generating a fluorescence response signal, whereby the multichannel laser output is modulated thereby modulating the heating at a predetermined frequency, thereby modulating the fluorescence response signal;
• a photomultiplier tube configured to capture the fluorescence response signal;
• and
• a controller configured to:
• process the captured modulated fluorescence response signal into two IR absorption spectra corresponding to chemical properties of two components in the sample by scanning over each channel of the multichannel laser array;
• generate a binary mask associated with the two spectra;
• establish a cost function based on the generated binary mask;
• optimize the cost function by optimizing the binary mask;
• and
• selectively energize channels of the multichannel laser array based on the optimized binary mask thereby maximizing discrimination between the two components.