Publications by authors named "Hojun Chang"

Recently the world population with diabetes has increased significantly, and the market demand for noninvasive blood glucose monitoring has increased accordingly. Our previous study demonstrated the capability to detect glucose through the direct observation of glucose Raman fingerprint peaks from in vivo skin but using a benchtop device. From the perspective of commercialization, miniaturized devices are expected to make more impact on the market than bulky benchtop devices.

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Noninvasive blood glucose monitoring has been a long-standing dream in diabetes management. The use of Raman spectroscopy, with its molecular specificity, has been investigated in this regard over the past decade. Previous studies reported on glucose sensing based on indirect evidence such as statistical correlation to the reference glucose concentration.

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Article Synopsis
  • - We discovered room-temperature lasing from photonic crystal structures made of Si3N4 and coated with colloidal quantum dots (CQDs) for optical gain.
  • - The lasing occurs in two different modes, influenced by how thick the CQD layer is.
  • - This new laser technology could greatly affect future integrated photonic circuits, as it allows easy connection between active and passive components on the same chip.
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This study proposes a one-dimensional sub-wavelength grating structure on GaN surface which behaves as a reflector for transverse-electric polarized light in the blue wavelength range. The rigorous coupled-wave analysis method was used to analyze the effects of various structural parameters on the reflectance spectra of the grating. Based on the optimal design, a GaN surface grating reflector (SGR) was fabricated using holographic lithography and dry etching processes.

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