This dataset consists of optical photothermal infrared (O-PTIR) images of two lung cancer cells (H1299). The cells were fixed before imaging. Enclosed files: image_Fixed_LungCancer_cell1.cdf: hyperspectral image of cell 1 image_Fixed_LungCancer_cell2.cdf: hyperspectral image of cell 2 spectra.cdf: spectra of cell 2 All files are in netCDF format. Hyperspectral images The images have four dimensions wavenumber: spectral axis x: fast axis y: slow axis trace_retrace: direction of movement during recording the image The associated coordinates are: xpix: pixel position in x ypix: pixel position in y trace: boolean trace/retrace pixel_size_X: size of pixel in x in nanometers pixel_size_Y: size of pixel in y in nanometers x_len: size along x in nanometers y_len: size along y in nanometers duty_cycle: duty cycle of laser during recording wavenumber: wavenumber of this image Each image contains six channels which are 4D ( wavenumber, trace_retrace,y,x) 64 bit float arrays: X: lock-in amplifier X component Y: lock-in amplifier Y component auxin1: voltage corresponding to probe laser brightness power_x: lock-in X component of MCT detector signal power_y: lock-in Y component of MCT detector signal The amplitude signal calculate from X and Y is the raw O-PTIR signal. It is normalized to the IR laser power by dividing by the amplitude of power_x and power_y and normalized to the sample transmission by dividing by auxin1. Spectra The spectra have two dimensions wn: spectral axis spec_index: spectral_index The associated coordinates are: wn: spectral axis in wavenumbers (cm⁻¹) pos_x: x position [nm] pos_y: y position [nm] Each image contains six channels which are 4D ( wavenumber, trace_retrace,y,x) 64 bit float arrays: x: lock-in x channel y: lock-in y channel frequency: laser repetition rate in hertz phase: lock-in phase dio: ? trigger: ? auxin0: DC signal of ? amplitude: lock-in amplifier amplitude power: laser power