CytoViva Optical Performance

CytoViva allows one to achieve optimized resolution and detection over traditional optical imaging techniques with living, fixed or non-biological samples. These capabilities result primarily from the exceptional contrast (high signal to noise ratio), which allows utilization of non-diffraction limited phenomena and improved point spread function.

This improved signal to noise ratio performance is achieved through:

  • The precise optical alignment in the fixed geometry of the unit
  • Ultra-efficient management of light within the optical path of the unit
  • Producing both Koehler illumination and main features of critical illumination

The resolving power of a microscope depends on the properties of the objective and the degree of coherence of the light incident upon the object. With traditional Critical illumination, a uniformly bright light source is placed close behind a diaphragm and is imaged by a condenser on to an object plane of a microscope objective. The light source is focused on the object. With traditional Koehler illumination, a converging (collimating) lens is placed close to the diaphragm and forms an image of the source light in the focal plane of the condenser, which includes a condenser diaphragm. Rays from each light source point then emerge from the condenser as a parallel beam. The light source is focused on an aperture of the condenser.

With CytoViva, complete Koehler illumination and a main feature of Critical illumination are achieved using a novel illumination system. Koehler illumination is pre-aligned in the device by fixing the light source precisely on the entrance slit of the condenser. This allows the user to adjust a focus point on the sample, which is a useful feature of Critical illumination, and is achieved when the condenser is aligned with the objective to find the focal point on the sample. Thus, Koehler illumination is initially fixed, and then CytoViva can be adjusted (up or down) to find the proper position and size of an illuminated spot for Critical illumination. Both Koehler and Critical illumination are not generally achievable in traditional microscopy. The resulting high signal to noise ratio of CytoViva allows the user to observe previously obscured non-diffraction limited optical effects.

The resolution of conventional optical microscopy is limited by the wave nature of light and is conventionally defined by the Rayleigh criterion; this is commonly referred to as diffraction limited resolution (limit of ~240 nm). With CytoViva, non-diffraction limited optical effects and an improved point spread function are produced that extend its resolution well beyond diffraction limits.*

*90nm (lambda/5) resolution in optical transmission microscope with annular condenser: Optics Letters, Vol. 31, Issue 19, pp. 2855-2857 Arnold Vainrub, Oleg Pustovyy, and Vitaly Vodyanoy.