UC San Diego

Optical signatures of the biological tissues and spectral characteristics of the chemotherapy agents provide distinctive information on the nature of these tissues and the chemical properties of the chemotherapy drugs delivered at the tumor sites. Equipping the tools routinely used in interventional procedures, with optical guidance could provide real-time feedback on the characteristics of the tissues and the drugs under examination by acquiring and evaluating their spectral information. A new optically guided needle system is designed here that transmits the spectrally encoded modulated light to the medium at the tip of the needle and processes the detected backscattered light to sense the presence of the blood or bile within the liver parenchyma, differentiate the benign and malignant breast tissue, activate a photocleavable prodrug and estimate the amount of the drug accumulated at the tumor site.

In addition to spectral imaging of the tissues, spatially encoded light fields were used to generate images of the objects hidden within scattering materials and methods were proposed to calculate and generate the desired spatially encoded vectorial fields at the focus of high NA lenses. The results of the imaging through scattering experiments showed that utilizing the designed set of spatially encoded projection patterns significantly reduced the number of measurements required to reconstruct an image of the hidden objects. The developed reflective imaging setup is compatible with the majority of the bio-imaging settings.

To generate the desired spatially encoded vectorial light fields at the image plane of the high NA lenses, a new method was proposed to calculate the required incident fields with spatially varying polarizations in the back focal plane of the lenses. With the refresh rate of 40 Hz for calculating 128128-pixel incident fields, this method could be used to update and adjust the designed focused fields in near real time. The application of this method in generating line traps for imposing translational movement on the trapped

particles was also discussed.