Pulse control in a wide frequency range for a quasi-continuous wave diode-pumped cesium atom vapor laser by a pump modulation in the spectral domain.

Diode-pumped alkali-atom laser (DPAL) has attracted intense attention due to its inherently high quantum efficiency, a good beam quality, and a high potential in the power scaling. However, most of DPAL research has been confined to the continuous wave and only a few pulsed operations have been attempted with limited performances. Here, we proposed and experimentally demonstrated a new scheme using a fast mode-hopping in the pump laser diode (LD), which enabled the quasi-continuous-wave (QCW) pulse modulation in a cesium (Cs) DPAL to control both the pulse width and the repetition rate.

Optical dispersion control in surfactant-free DNA thin films by vitamin B doping.

A new route to systematically control the optical dispersion properties of surfactant-free deoxyribonucleic acid (DNA) thin solid films was developed by doping them with vitamin B, also known as riboflavin. Surfactant-free DNA solid films of high optical quality were successfully deposited on various types of substrates by spin coating of aqueous solutions without additional chemical processes, with thicknesses ranging from 18 to 100 nm. Optical properties of the DNA films were investigated by measuring UV-visible-NIR transmission, and their refractive indices were measured using variable-angle spectroscopic ellipsometry.

Enhanced optical transmission through a star-shaped bull's eye at dual resonant-bands in UV and the visible spectral range.

Dual resonant bands in UV and the visible range were simultaneously observed in the enhanced optical transmission (EOT) through star-shaped plasmonic structures. EOTs through four types of polygonal bull's eyes with a star aperture surrounded by the concentric star grooves were analyzed and compared for 3, 4, 5, and 6 corners, using finite difference time domain (FDTD) method. In contrast to plasmonic resonances in the visible range, the UV-band resonance intensity was found to scale with the number of corners, which is related with higher order multipole interactions.