fabrication techniques for device fabrication in contrast to inorganic counterpart materials, such as silicon (Si) and silicon nitride (SiN). As a result, optical polymers are increasingly seen as cost-effective solutions for manufacturing photonic devices in high volume. Despite these numerous processing advantages, optical polymer materials for integrated photonics remain limited relative to inorganic materials with respect to critical optical properties, especially refractive index (n, or RI). The vast majority of current optical polymers have a refractive index ranging between 1.3-1.6 at telecom wavelengths, which is significantly lower than the RI values of SiN, lithium niobate (n ≈ 2.0-2.2), or higher RI materials such as Si, [9,10] indium phosphide, or germanium (n ≈ 3.5-4.0). Because of these dramatically lower RI values, on-chip integrated photonic components, such as waveguides or ring resonators fabricated using optical polymers require much larger feature sizes beyond what is tenable for numerous on-chip device systems and preclude the fabrication of curved features with tight bend radii which are essential integrated optical elements. With an ever-increasing demand for high density integrated optical circuitry, the large areal footprint of state-of-the-art polymer devices due to limited RI contrast remains a critical limitation toward realizing all-polymer photonic circuits for high density interconnects and integration. Hence, there is a compelling technological need for high RI polymers (n >> 1.6 at telecom at 1310 and 1550 nm) that are amenable to thin film processing and high throughput nano/ microfabrication techniques (e.g., photolithography). There are a handful of inorganic materials, such as Hydex glass [11,12] and silicon oxynitride (SiON), [13] which have been studied to create inexpensive, earth-abundant inorganic materials that achieve RI values ranging from n = 1.6-2.0 at telecom wavelengths. Furthermore, recent work on solution-processable chalcogenide glasses (ChGs) has been explored to create thin films and integrated photonic components, such as single-mode waveguides in the mid-wave infrared (MWIR), which exploit the high RI and high transparency ChGs. [14][15][16][17] However, fabrication processes for these materials remain non-trivial, requiring multi-step high temperature methods, or the use of unconventional toxic solvents which has limited wide-scale deployment. Numerous Optical polymer-based integrated photonic devices are gaining interest for applications in optical packaging, biosensing, and augmented/virtual reality (AR/VR). The low refractive index of conventional organic polymers has been a barrier to realizing dense, low footprint photonic devices. The fabrication and characterization of integrated photonic devices using a new class of high refractive index polymers, chalcogenide hybrid inorganic/organic polymers (CHIPs), which possess high refractive indices and lower optical losses compared to traditional hydrocarbon-based polymers, are reported. These optical polyme...

We have developed a low-cost, chromatic confocal endomicroscope (CCE) that can image a cross-section of the tissue at cellular resolution. In CCE, a custom miniature objective lens was used to focus different wavelengths into different tissue depths. Therefore, each tissue depth was encoded with the wavelength. A custom miniature spectrometer was used to spectrally-disperse light reflected from the tissue and generate cross-sectional confocal images. The CCE prototype had a diameter of 9.5 mm and a length of 68 mm. Measured resolution was high, 2 µm and 4 µm for lateral and axial directions, respectively. Effective field size was 468 µm. Preliminary results showed that CCE can visualize cellular details from cross-sections of the tissue in vivo down to the tissue depth of 100 µm.

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