Research in the So Lab

High-speed Handheld Minaturized Multiphoton Multifocal Microscopy (H²M⁴)

Investigators: Daekeun Kim, Ki Hean Kim, Siavash Yazdanfar

High-speed handheld miniaturized multiphton multifocal microscopy (H2M4) is being developed mainly for the purpose of optical biopsy, a promising alternative to histological analysis. The noninvasive nature of optical biopsy requires imaging device which has high speed imaging capability to avoid motion artifacts during imaging, ergonomic design for easy access subjects and light source delivery without any distortion.

High speed imaging can be achieved with multiple foci excitation/detection simultaneously, which increase laser dwelling time with high contrast, and decrease image acquisition time on the tissue. these are implemented with microlens array and multianode photon multiplier tube (MA-PMT).

The key of ergonomic design is compactness. To meet compactness, optical elements with relatively short focal length should be used. Accompanying them, the compact-size piezo-driven tip/tilt mirror is selected as a laser scanning device since it can work in electromagnetic wave free envoronment, and provides enogh bandwith to achieve high speed imaging. The use of tip/tilt mirror can also reduce the nonuniform excitation commonly shown in xy laser scanning system.

The use of photonic crystal fiber (PCF) provides decrease of pulse broadening of femto-second pulsed laser, light source of multiphoton microscopy, during using conventional fibers. We are under investigation for commercially available one in order to observe multiphoton efficiency.