Photothermal Spectroscopy Corp
Photothermal Spectroscopy Corp (PSC) is a Santa Barbara, CA, based scientific equipment company that pioneered the sub-micron IR technique, Optical Photothermal Infrared Spectroscopy (O-PTIR) and recently sub-micron Photothermal Stimulated Raman Spectroscopy (PT-SRS).
PSC’s vision is to enable the power of sub-micron, multimodal Photothermal IR and Raman spectroscopy to be applied to high value problems in Life Science and Pharmaceuticals research and via the adoption of thses unique techniques.
mIRage-HSi IR Multimodal Microscope
Multimodal Optical Photothermal infrared spectroscopy (O-PTIR) used on the mIRage microscopes is a result of nearly 2 decades of expertise in photothermal based IR spectroscopy.
mIRage-HSi combines sub-500 nm O-PTIR chemical imaging with laser-scanning speed, revealing label-free distributions of key macromolecules like lipids, proteins and nucleic acids while also resolving micro- and nanoplastic particles in complex biological samples.
Hyperspectral images are acquired in minutes and targeted single-wavenumber images in seconds, making detailed cellular studies and high-throughput particle workflows practical.
The mIRage-HSi supports multi-modal capabilities with simultaneous raman, co-located fluorescence microscopy and optical microscopy making it a powerful instrument for high resolution life science research.
O-PTIR: How it works
O-PTIR overcomes the IR diffraction limit by combining a mid-IR pulsed, tunable laser that heats the sample. When the IR laser is at a wavelength that excites a molecular vibration in the sample, absorption occurs, thereby creating photothermal effects including photothermal expansion. A visible probe laser, focused to 0.5 µm spot size, measures the photothermal response via the scattered light, as shown in the illustration above.
The component of the reflected visible laser signal that is modulated at the IR pump laser repetition rate is directly proportional to the absorption coefficient of the sample at that wavenumber. The IR pump laser can be tuned through the entire fingerprint region in one second or less, to obtain an IR spectrum.
By operating in reflection mode, O-PTIR eliminates several longstanding limitations and has substantial benefits for the IR community, including sub-micron resolution using a non-contact optical method. The sub-micron resolution is demonstrated (right), showing reflection mode spectra on a multi-layer packaging film measured 0.5 µm apart with highly differentiated chemical fingerprints indicating different materials.
Measurements are collected quickly and easily without need for sample contact, unlike ATR spectroscopy. Additionally, O-PTIR provides spectra comparable to FTIR without the dispersive artifacts observed in ATR. By operating in reflection mode, the need for thin samples is also eliminated, leading to dramatically easier sample preparation and faster turnaround times.