Two photon spectroscopy

We study two photon absorption (2PA) spectra and cross sections in organic chromophores - polyenes, dendrimers, aggregates, porphyrins, phthalocyanines, corroles etc. Our goal is to find what determines the NLO response and how to increase 2PA cross section. In collaboration with organic synthetic groups, we design and create new 2PA-enhanced molecules for various  applications, such as optical limiting, 3D storage, PDT and 2PA microscopy.

 

Optical Memory

We study  organic photochromes for  2PA-based terabyte rewritable volumetric optical data storage. Writing of the data bits is performed by means of 2PA-induced photochromic switching, and  reading out is performed by 2PA-induced fluorescence. Single-channel data access rate > 100 MHz, together with SNR>4 requires minimum 2PA cross section, s₂ > 10³ GM. Our approach to drastically increase the value of s₂ is by using near-resonance excitation, which allows  s₂ ~ 10⁵ GM.

 

Photodynamic Therapy

We have developed a novel therapeutic agent comprising of a patented 2PA-enhanced porphyrin core conjugated to a cancer cell targeting unit and near-IR fluorescence imaging dye. Together  these components form one multi-functional nano-photonic construct for beep penetration non-invasive, image-guided photodynamic therapy (PDT).  We have shown that various types of cancer tumors can be significantly regressed by illumination with near-IR femtosecond laser pulses.