1. One-Color Reversible Control of Photochromic Reactions in a Diarylethene Derivatives: Three-Photon Cyclization and Two-Photon Cycloreversion by a Near-Infrared Femtosecond Laser Pulse at 1.28  m K.Mori et al, J.Am.Chem.Soc. 2011, 133, 2621-2625 Miyasaka Lab. Naoaki Yasuda 1

2. Contents Introduction ・ Photochromic reactions in a Diarylethene Derivative ・ Nonresonant High-order Multiphoton Absorption ・ Multiphoton Absorption in Photochromic reactions Methods ・ Optical Setup ・ Sample Results Summary My Work 2

3. Photochromic Reactions in a Diarylethene Derivative UV Vis. Open-ringClosed-ring Changes in property Color Refractive indices Dipole moments Thermal stability Repetition durability Reactivity in solid Photochromic compounds can interconvert its molecular structure by photoirradiation 3

4. Photochromic Reactions in a Diarylethene Derivative Photoinduced Twisting of a Photochromic Diarylethene Crystal D. Kitagawa et al, Angew. Chem. Int. Ed., 52, 9321 (2013) 4

5. Photochromic Reactions in a Diarylethene Derivative Photoinduced Bending of a Photochromic Diarylethene Crystal Scale Bar : 3  m S. Kobatake et al, Nature, 446, 778 (2001) 5

6. Photochromic Reactions in a Diarylethene Derivative Application to photonic device with molecular level resolutions M. Morimoto and M.Irie, J. Am. Chem. Soc., 132, 14177 (2010) Two kinds of laser sources are required 6

7. Nonresonant High-order Multiphoton Absorption Two-photon absorption Three-photon absorption In the case of irradiating 1280 nm pulsed laser SnSn S0S0 640 nm 427 nm S0S0 SnSn Reproduce other range of wavelength with one laser source 1280 nm 7

8. Multiphoton Absorption in Photochromic Reactions By changing laser intensity, we can control directions of photochromic reactions Three-photon absorption Two-photon absorption High Intensity Weak Intensity Closed-ring Open-ring SnSn S0S0 SnSn S0S0 8

9. Optical Setup CW Nd: Vanadate Laser(1064 nm) Prism Pair Cr: F crystal Bragg cell 1280 nm Home-built Cr:F Laser H. Matsuda et al, J. Phys. Chem B, 110, 1091 (2006) Spectrum of Laser Output 9

10. Optical Setup Home-built Cr:F laser Prism Pair Periscope Telescope Microscope CCD Fiber-coupled spectrometer Pulse width : 35 fs Three-photon Fluorescence Scale bar : 5  m Four-photon Fluorescence 10

11. Sample 1,2-bis(5-{4-[N,N-bis(4-methylphenyl)amino]phenyl}- 2-methylthiophen-3-yl)-3,3,4,4,5,5-hexafluorocyclopentene Absorption Spectra Spin coating at 3000 rpm Amorphous Film Open-ring Closed-ring 11

12. 1 nJ, 50 ms irradiation 75 pJ, 300 s irradiation Controlling photochromic reactions by varying intensity 75 pJ, 300 s irradiation Colored Decolored Colored again 12

13. Controlling photochromic reactions by varying intensity Absorption Spectrum of the colored area Red line : the steady-state difference spectrum between closed and open forms of sample. Colored 13

14. Controlling photochromic reactions by varying intensity Three-photon absorption Two-photon absorption Closed-ring Open-ring 14

15. Space-Resolved Patterning by One-Color Photochromic Reactions Transmittance images Laser Profile The center (Strong Intensity) ⇒ Three-Photon Absorption Around the center (Low Intensity) ⇒ Two-Photon Absorption 15 600 nm

16. Summary ●One-color reversible photochromic reactions became possible by inducing multiphoton absorption with femtosecond pulsed laser. ●One-color reversible photochromic reactions are also applied to spatial patterning. 16

17. Nonresonant High-order Multiphoton Absorption One-photon absorption Laser Lense Two-photon absorption Laser Lense http://www.imaging-git.com/science/light-microscopy/optogenetics- relies-multiphoton-microscopy 17

18. My work Multiphoton Absorption Tiny spot along the optical axis ⇒ Microfabrication ⇒ Multilayer memory storage Scale bar : 2  m S. Kawata et al, Nature, 412, 697 (2001) http://www.jontyhurwitz.com/nano/ Scale bar : 10  m 18

19. My work Laser Source : Tunable Pulsed Laser Sample : Fluorescent Diarylethene Derivatives 700 nm ～ 1080 nm Closed-ring Open-ring Closed-ring Open-ring M. Morimoto et al, CrystEngComm, (2016) DOI : 10.1039/C6CE00725B 19

20. My work Ti:Sapphire 700 nm ~ 1080 nm PrismA PrismB BS PS SPFAPD L1 L2 DM 対物 ODL ND Sample 20

21. Photochromic Reactions in a Diarylethene Derivative 21

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23. Photochromic Reactions in a Diarylethene Derivative Real-Time Dynamic Hologram with Fast Photochromic Molecules Y.Kobayashi and J.Abe, ADVANCED OPTICAL MATERIALS 23

24. Multiphoton Absorption in Photochromic Reactions 24