We report on a novel nanoparticle platform by electric field assisted assembly, which is capable of manipulating the refractive index distribution through controlling the particle assembly. Two examples based on the control of the scattering properties are presented. We demonstrate lensless imaging in such a system. In addition, we show that random lasing can be enhanced by assembly of anisotropic particles immersed in a gain medium. These examples illustrate that particle assembly technique provides a promising platform for reconfigurable optical applications.
We presented a broadly tunable, power scalable, multi-line, ultrafast source. The source is based on combining principles of pulse division with the phenomenon of the soliton self-frequency shift. By using this system, interferometric pulse recombination is demonstrated showing that the source can decouple the generally limiting relationship between output power and center wavelength in soliton self-frequency shift based optical sources. Broadly tunable multi-color soliton self-frequency shifted pulses are experimentally demonstrated. Simultaneous dual-polarization second harmonic generation was performed with the source, demonstrating one novel imaging methodology that the source can enable.
The turbidity of biological tissue due to fundamental light-tissue interactions has been a long-standing challenge in biomedical optical technologies. Implanting fibrous optical waveguide into tissue and organ for light delivery and collection is one of the most effective way for alleviate this problem. In this manuscript, by taking advantage of the favorable designability and processibility of citrate-based synthetic polymers, two bio-elastomers with distinct optical properties but matched mechanical properties and similar biodegradation profiles were developed. Combining with an efficient two-step fabrication method, we created a new biodegradable and biocompatible step-index optical fiber. Benefited from this step-index structure and high tunability of citrate-based bio-elastomers, our optical fiber not only demonstrated outstanding optical performance (0.4dB/cm loss), but also had favorable mechanical and biodegradable properties. Apart from the fabrication and characterization of our optical fiber, we successfully demonstrated the functionalities of multimode fiber imaging, deep tissue light delivery and in vivo fluorescence detection of our newly designed optical fiber. We believe the flexible, biodegradable and low loss optical fiber designed in our work offers a valuable tool for optical applications including imaging, detecting, sensing, optogenetic stimulation, and treatment to target regions underneath deep tissue.
Chloride level in sweat is a major diagnostic criterion for cystic fibrosis (CF) and many other health conditions. In an effort to develop a low cost, point-of-care sweat diagnostics system for chloride concentration measurement, we demonstrated a smartphone-based chloridometer to measure sweat chloride by using our recently developed fluorescence chloride sensor. We characterized the performance of our device to validate its clinical potential. The study indicates that our smartphone-based chloridometer may potentially advance the point-of-care diagnostic system by reducing cost and improving diagnostic accuracy.
Biocompatible and even biodegradable polymers have unique advantages in various biomedical applications. Recent years, photonic devices fabricated using biocompatible polymers have been widely studied. In this work, we manufactured an optical fiber using biodegradable polymer POC and POMC. This step index optical fiber is flexible and easy to handle. Light was coupled into this polymer fiber by directly using objective. The fiber has a good light guiding property and an approximate loss of 2db/cm. Due to the two layer structure, our fiber is able to support applications inside biological tissue. Apart from remarkable optical performance, our fiber was also found capable of performing imaging. By measuring the impulse response of this multimode polymer fiber and using the linear inversion algorithm, concept proving experiments were completed. Images input into our fiber were able to be retrieved from the intensity distribution of the light at the output end. Experiment result proves the capability of our optical fiber to be used as a fiber endoscopy no needs to remove.