Tissue & imaging

Biomedical optics measures how tissue, blood and biomolecules absorb, scatter and emit light. A compact spectrometer turns those interactions into quantitative data for research instruments and for OEM systems built by medical device manufacturers. Evolve Sensing supplies spectrometers as components for these systems. Clinical certification of a finished device is carried out by the system manufacturer.

Blood oximetry and co-oximetry

Hemoglobin species have distinct absorption spectra in the visible range. Oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin and methemoglobin differ most strongly between about 500 and 670 nm, and bilirubin absorbs near 454 nm. A co-oximeter records the full absorbance spectrum of a hemolyzed sample and solves for each species by multicomponent regression. The method depends on wavelength accuracy and low, stable stray light, because small shifts in the spectrum bias the fitted fractions.

Pulse oximeters use two LEDs, typically near 660 and 940 nm. Spectrometers support that work in the development laboratory, where engineers characterize LED emission, sensor optics and tissue phantoms.

Tissue reflectance and fluorescence

Diffuse reflectance spectroscopy sends broadband light into tissue through a fiber probe and collects the light that returns. Absorption from hemoglobin and water, together with scattering from cell structure, shapes the returned spectrum. The 650 to 950 nm region, often called the optical window, allows the deepest penetration because both hemoglobin and water absorb weakly there.

Autofluorescence adds metabolic information. NADH excited near 340 nm emits near 460 nm, and FAD excited near 450 nm emits near 525 nm. Researchers also study skin autofluorescence from advanced glycation end-products, excited in the near UV. These measurements call for UV-Vis spectrometers with high sensitivity and low stray light, since fluorescence signals are weak compared with the excitation.

Optical coherence tomography

Spectral-domain OCT builds depth-resolved images of the retina, skin and other tissue from interference between a reference arm and light scattered in the sample. A line-scan spectrometer records the interference spectrum, and a Fourier transform converts it to a depth profile. Source bandwidth sets the axial resolution, while the spectral sampling interval per pixel sets the maximum imaging depth. Spectrometer resolution sets how quickly sensitivity falls off with depth. Systems near 840 nm are common for ophthalmology, and systems near 1310 nm reach deeper in scattering tissue.

Evolve Sensing offers the Alpha OCT and Delta OCT spectrometers for 840 nm band engines, with high line rates and the resolution needed for long imaging depth.

Phototherapy and light dosimetry

Neonatal jaundice is treated with blue light between about 430 and 490 nm, where bilirubin absorbs. Dermatology and photodynamic therapy use other bands in the UV, visible and red. In each case the delivered dose depends on spectral irradiance at the treatment surface. A spectrometer with an irradiance calibration and a cosine corrector reports that value in µW/cm²/nm, which supports source development, device testing and routine checks of therapy lamps.

Evolve Sensing for biomedical instruments

• Alpha OCT and Delta OCT: spectrometers for spectral-domain OCT engines.
• EagleEye: TE-cooled UV-Vis-NIR for low-light fluorescence and reflectance.
• Magna and Phenom: high-resolution platforms for research instruments.
• Trigger inputs, SDK support and OEM configuration for instrument builders.

We are happy to help match a spectrometer to a research setup or a device design.