Shinji Tanosaki

Lasing behavior in a liquid spherical dye laser containing highly scattering nanoparticles.

With the addition of scattering nanoparticles to dye-doped spherical droplets, lasing has been observed with well-defined thresholds in input-output data. One-order or more magnitude enhancement of peak intensity from droplet emission has been obtained with certain (optimum) additive scattering particles compared with nonadditive scattering particles (neat dye-doped droplets). Characteristics of input-output intensities, emission spectra (with wavelength shifts), and spectral linewidths are reported experimentally, depending on additive quantities of scattering nanoparticles.

Experimental studies on output, spatial, and spectral characteristics of a microdroplet dye laser containing Intralipid as a highly scattering medium

Lasing characteristics of Rhodamine 6G dye-doped microdroplets containing highly scattering fat emulsion Intralipid-10% are studied experimentally. Noteworthy findings are that well-defined lasing threshold can be observed and one order or more magnitude enhancement of emission intensity with suitable (optimum) conditions of the Intralipid mixing ratio, in comparison with original neat-dye lasing microdroplets. We present and discuss the measured results of input-output intensities for different dye concentrations and dye-Intralipid mixing ratios in this high-gain laser dye-soft scatterer system and microscope images of spatial distribution of light emission from both the microdroplets containing neat-dye and dye-Intralipid mixture. It was found that almost no-lasing neat-dye microdroplets, which have either much higher or much lower dye concentration, can achieve lasing by substituting suitably certain amounts of the Intralipid, causing multiple light scattering. Spectral measurements of lasing outputs from the Rhodamine 6G dye-Intralipid microdroplets show the tendency of the disappearance of the well-known mode structures, owing to the morphology-dependent resonances of this microspherical cavity inherent to the neat-dye microdroplets. It is our belief that the present results make this novel method of dye-Intralipid microsystem very attractive for a variety of future applications, including diagnostic tools for highly sensitive detection and identification of small quantity objects and species embedded or hidden in highly scattering media, such as biological tissues and cellular structures.

Microdroplet dye laser enhancing effects in dye-highly scattering intralipid mixture

The significant effect of fat emulsion intralipid‐10% mixing on lasing behaviors of liquid microdroplets was studied using rhodamine 6G dye. This highly scattering medium allows one to make the high‐gain laser dye‐soft scatterers microsystems that can provide well‐defined lasing threshold and one‐order or more magnitude enhancement of emission intensity with suitable (optimum) conditions of the mixing ratio, in comparison with original neat‐dye lasing microdroplets. We also present and discuss the measured results of input–output intensities for different dye concentrations and dye‐intralipid mixing ratios, and microscope images of spatial distribution of emission from both the microdroplets containing neat‐dye and dye‐intralipid mixture.

Three-Color Whispering-Gallery-Mode Dye Lasers Using Dye-Doped Liquid Spheres

A multiple laser operation in blue, green and orange spectral regions (3-colors) due to whispering-gallery mode (WGM) using dye-doped liquid spheres, by UV N2 laser pumping, was achieved. A technique of forming liquid spheres with stable droplet-size and fundamental characteristics concerning the energy-transfer effects in dye mixtures are also presented.

Laser emission from dye-doped small spheres by ultraviolet N2 laser pumping

A small spherical dye laser containing rhodamine 6G pumped by a compact TEA UV-N2 laser is reported. Small spheres of good quality are observed under the microscope. The lasing characteristics of the spherical dye laser are different from the usual bulk dye laser, with respect to the direction of the laser beam. The former is oriented in all directions while the latter is unidirectional. The waveform and spectral characteristics from the dye-doped small spheres show lasing in the whispering-gallery modes.

Whispering‐gallery‐mode dye lasers in blue, green, and orange regions using dye‐doped, solid, small spheres

A whispering‐gallery‐mode (WGM) dye laser in blue, green, and orange regions is reported using dye‐doped, solid, small spheres. A WGM dye laser is pumped by a transversely excited atmospheric UV N2 laser. Some features of the WGM dye laser are demonstrated.

Multiple oscillation of whispering-gallery-mode dye lasers in green and orange regions using mixed-dye-doped solid microspheres

Mixed‐dye‐doped solid microspheres are excited by a transversely excited‐atmospheric ultraviolet N2 laser to obtain a multiple oscillation of a whispering‐gallery‐mode (WGM) dye laser in both green and orange regions. The multiple oscillation exhibits separate modes of WGMs in both spectral regions.

Highly scattering Intralipid-10% assisted lasing from microdroplets with Acridine Orange dye

One order or greater of magnitude enhancement of lasing emission is confirmed experimentally from liquid microdroplets of Acridine Orange dye mixed with the fat emulsion Intralipid-10% suspension as highly scattering media, compared with pure dye-doped droplets. This novel method that makes use of a high-gain laser dye soft scatter microsystem allows for a wide range of lasing of microdropslets. Originally without lasing pure dye droplets enabled one to lase with a well-defined threshold and an appreciably increased emission intensity in suitable conditions. Spectral characteristics and emission peak intensities from these microdroplets are measured quantitatively as a function of volume content of Intralipid-10% solutions.

Inexpensive operating system for whispering‐gallery‐mode laser using dye‐doped solid small spheres

A simple and inexpensive system is reported for a whispering‐gallery‐mode (WGM) laser using a dye‐doped solid small sphere. A WGM laser is pumped by a compact transversely excited atmospheric (TEA) UV N2 laser. Experiments using the inexpensive system and some features in the WGM laser are demonstrated.

New biochemical material laser emission in microdroplets using ribo-flavin and its enhancement by mixing highly scattering intralipid medium

New laser emission from a biochemical material, ribo-flavin (vitamin B2), at 570 nm was observed for the first time in liquid microdroplets pumped at 475 nm using a pulsed optical parametric oscillator. Laser emission spectra from microdroplets containing ribo-flavin in water and glycerol solution exhibit periodic mode structures depending on the microdroplet diameter demonstrating the morphology-dependent resonances. Magnitude enhancement of lasing emission is confirmed experimentally from liquid microdroplets of ribo-flavin solution with appropriate mixture of the fat emulsion Intralipid-10% suspension as highly scattering medium. We believe that such biochemical-soft multiple light scatterer systems may allow a wide range lasing of other bio-materials and even lead to the discovery of some novel species as well as highly sensitive analysis and diagnosis for future applications.