Presentation is loading. Please wait.

Presentation is loading. Please wait.

Fabrication of whispering gallery modes microcavity during optical trapping ASHIDA LAB TOYOTA YUSUKE.

Similar presentations


Presentation on theme: "Fabrication of whispering gallery modes microcavity during optical trapping ASHIDA LAB TOYOTA YUSUKE."— Presentation transcript:

1 Fabrication of whispering gallery modes microcavity during optical trapping ASHIDA LAB TOYOTA YUSUKE

2 Contents Introduction ・ optical cavity ・ whispering gallery modes (WGM) microcavity Motivation Radiation force Experimental method & set up Result Future plan

3 Optical cavity d 2d = n λ resonate application ・ laser ・ increase of non-linear optical effect ・ light amplifier vacuum

4 Q-factor & mode volume Q = τ ν τ : photon lifetime in cavity ν : resonance frequency d loss mode volume the smaller mode volume become, the more light reflect. low Q-factor many losses

5 WGM Microcavity High Q-factor despite small mode volume Wave optics LASER Wave LASER Geometric Geometric optics

6 Mode number n, m, l Mode number n, m, l For example A variety of mode numbers make a variety of mode patterns. Fundamental WGM n n = 1 Kippenberg, T.J.A. Nonlinear optics in ultra-high-Q whispering-gallery optical microcavities. (2004). at

7 l Mode number l l = 4 l = 3 half wavelength

8 m Mode number m m = 0 m = l - 2 m = l m = 0 m = l - 2 m = l

9 Free spectra range Wavelength Oblate sphere sphere l = 2 l = 3 l = 4 l = 2 l = 3 l = 4 intensity

10 Previous work sample Ablation laser Laser ablation in superfluid HeMelting of optical fiber CO2 laser Optical fiber 2 K Fabricate Multiple microcavities at one time Impossible to select size Oblate sphere Limited material Possible to select size

11 Motivation Size selectivity, high sphericity, a variety of material Optical trap trap beam CO2 laser surface tensionHow to form sphere ??

12 Radiation force Gradient force Dissipative force Optical manipulation Optical trap

13 Experimental method Dual beam trap Gradient force Optical trap Dissipative force d important important d d is longer than that of single beam trap.

14 Optical trap Optically trapped single SiO2 microsphere

15 Set up Ti:sapphire laser 784 nm, 1.8 W CO2 laser 10.6 μm Polarized BS L1 L2 CF White light spectrometer λ/2 L1 White light spectrometer 90° L1 f = 8.00 mm NA = 0.5 L2 f = 100 mm

16 Experimental step Gradient force Optical trap Ultrasonic nebulizer Ethanol droplet : silica = 3000 : 1

17 Experimental step ① Measure scattering light White light CO2 laser ② Melt ③ Measure scattering light again

18 Result

19 Blue shift

20 Result Blue shift

21 Summary We achieved optical trapping of a single SiO2 microsphere and observed WGM spectra. We melted the optically trapped single SiO2 microsphere and observed blue shift of the WGM spectra.

22 Future plan White light CO2 laser Semiconductor microparticle (NOT sphere)


Download ppt "Fabrication of whispering gallery modes microcavity during optical trapping ASHIDA LAB TOYOTA YUSUKE."

Similar presentations


Ads by Google