A numerical model based on a scalar beam propagation method is applied to study light transmission in photonic bandgap (PBG) waveguides. The similarity between a cylindrical waveguide with concentric layers of different indices and an analogous planar waveguide is demonstrated by comparing their transmission spectra that are numerically shown to have coinciding wavelengths for their respective ...

Fluorescent turn-on probes for nitric oxide based on seminaphthofluorescein scaffolds were prepared and spectroscopically characterized. The Cu(II) complexes of these fluorescent probes react with NO under anaerobic conditions to yield a 20-45-fold increase in integrated emission. The seminaphthofluorescein-based probes emit at longer wavelengths than the parent FL1 and FL2 fluorescein-based ge...

Most current approaches to multiantigen fluorescent imaging require overlaying of multiple images taken with separate filter sets as a result of differing dye excitation requirements. This requirement for false-color composite imaging prevents the user from visualizing multiple species in real time and disallows imaging of rapidly moving specimens. To address this limitation, here we investigat...

We present an investigation into the mechanism for guidance of microstructured optical fibers consisting of high-refractive-index cylinders embedded in a low-index background. A new guidance regime is identified in which the fibers' confinement losses depend strongly on wavelength and the positions of the loss minima and maxima depend on the scattering properties of individual cylinders and onl...

In the present work, gain of EDFA (Erbium Doped Fibre Amplifier) and YDFA (Ytterbium Doped Fibre Amplifier) are analyzed based on their performance parameters. The effects of pump laser power, length of doped fibre that used for amplification and the wavelength of the input signal on the gains of the optical amplifiers is examined. EDFA exhibits maximum gain of 48db around 1550nm regions with p...

We have measured the growth kinetics of gold nanoparticles in real time. Gold nanoparticles were formed from the reduction of gold (III) in aqueous solution and monitored with a stopped-flow reactor equipped with a diode array. The overall reduction of gold (III) occurred in less than 20 [ms]. The growth kinetics was determined from measurements of the plasmon resonance time-dependent wavelengt...

We experimentally demonstrate the dissipative soliton mode-locking operation of a Yb:YSO laser by using an all-normal dispersion cavity. Strongly chirped pulses are obtained with pulse duration of 9.3 ps at a repetition rate of 113.4 MHz. The central wavelength is 1082 nm with 3.1 nm FWHM bandwidth. A dual-wavelength synchronously mode-locking operation at central wavelengths of 1059.2 nm and 1...

For living deep-tissue imaging, the optical window favorable for light penetration is in near-infrared wavelengths, which requires fluorescent proteins with emission spectra in the near-infrared region. Here, we report that a single mutant Ser28His of mNeptune with a near-infrared (≥650 nm) emission maxima of 652 nm is found to improve the brightness, photostability, and pH stability when compa...

The photocycle of the photoactive yellow protein (PYP) from Ectothiorhodospira halophila was examined by time-resolved difference absorption spectroscopy in the wavelength range of 300-600 nm. Both time-gated spectra and single wavelength traces were measured. Global analysis of the data established that in the time domain between 5 ns and 2 s only two intermediates are involved in the room tem...

The ecological success of diatoms is emphasized by regular blooms of many different species in all aquatic systems, but the reason behind their success is not fully understood. A special feature of the diatom cell is the frustule, a nano-patterned cell encasement made of amorphous biosilica. The optical properties of a cleaned single valve (one half of a frustule) from the diatom Coscinodiscus ...