Dg10 220 md

The complete experimental set-up is presented in Fig. 3. A halogen source combined with a band pass filter (central wavelength λ = 550 nm) was introduced as a spatially incoherent illumination source. A rotating diffuser and a tube lens are placed before the input plane to ensure the beam to be totally incoherent and collimated. The focal length of the imaging lens is f = 150 mm and z₁ = z₂ = 2f, d ≈ 2f. The plaintext image is loaded on a SLM (Holoeye, LC2002) which was placed at the input plane and worked at the amplitude modulation mode. The RPM was a 220 grit-ground-glass diffuser (Thorlabs, DG10-220-MD). A high-resolution CMOS camera (Photonfocus, MV1-D2048-96-G2-10, resolution: 2048 × 2048 px, pixel size: 5.5 μm × 5.5 μm, active optical area: 11.26 mm × 11.26 mm) was placed at the output plane to capture the ciphertext (speckle pattern).

A multispectral SWIR fluorescence imaging system was designed and constructed (Fig. 2). Briefly, tissue is illuminated by a 785-nm fiber-coupled laser (BWF-1-785/55371, B&W Tek) dispersed onto the sample using a ground glass diffuser (DG10-220-MD, Thorlabs, Germany). SWIR fluorescence emission from the sample is collected by a highly sensitive InGaAs camera [ $\mathrm{QE}>80\%$ 950 to 1600 nm, NIRvana 640, Teledyne Princeton Instruments Fig. 2(b)] coupled to a SWIR lens ( $f=16\mathrm{mm}$ , F/1.4, Navitar, Canada). Fluorescence light is sequentially filtered using a six-position filter wheel (LTFW6, Thorlabs, Germany) through six long-pass filters with cut-off wavelengths of 850, 950, 1050, 1150, 1250, and 1350 nm [FELH series, Thorlabs, Germany, Fig. 2(b)]. The system was mounted inside a light-tight enclosure to remove background light. The camera was cooled to $-80°\mathrm{C}$ to reduce thermal noise.

A novel system was designed and constructed (Fig. 1). Briefly, tissue is illuminated by a 785-nm fiber-coupled laser (BWF-1–785/55371, B&W Tek) dispersed onto the sample using a ground glass diffuser (DG10–220-MD, Thorlabs). SWIR fluorescence emission from the sample is collected by a highly sensitive InGaAs camera (QE > 80% 950–1,600 nm, NIRvana 640, Teledyne Princeton Instruments) coupled to a SWIR lens (f = 16 mm, F/1.4, Navitar). Fluorescence light is sequentially filtered using a 6-position filter wheel (LTFW6, Thorlabs) through 6 long-pass filters with cut-off wavelengths of 850, 950, 1,050, 1,150, 1,250, and 1,350 nm (FELH series, Thorlabs). The system was mounted inside a light-tight enclosure to remove background light. The camera was cooled to −80°C to reduce thermal noise. Images were captured using LightField (Teledyne Princeton Instruments) and saved as 16-bit TIFs for analysis.