Modern Optics V- special issues on quantum optics Special topics course in IAMS Lecture speaker: Wang-Yau Cheng 2006/4

Outline Wave properties of light Polarization of light Concept of linewidth Coherence of light Special issues on quantum optics

–Introduction to the missions of “Quantum Control Laboratory” in IAMS

量子控制銫原子之研究 ── 人們的夢想：從了解微觀世界到控制微觀世界 Studies on Quantum Controlled Cs atoms -- A dream from comprehend to control the microscopic world

Outline Quantum controlled by femto-second comb laser What we need in improving the quantum control technique?

How come a God given quantum system can be controllable?

Quantum system determined by God Quantum system controlled by human being Photon quantum state Total quantum system then be controllable ! or Or … Atom wavefunction Ionization rate Molecule dynamics Cavity modes Electron-hole pair A quantum system may include: matter quantum states photon states

For example By controlling laser pulse, control P  to the maximum value Laser pulse Atom / molecule Dressed Atom/molecule Mixed state Sysem can be controlled to quantum state m 

Femto-second comb laser -- Introduction People now can prepare 10 5 photon coherent states at the same time !  f rep I(f) f  0 f rep I(f) f  0 f rep Time Domain Frequency Domain Time Domain Frequency Domain  t E(t)  1/f rep F.T. Phase velocity  Group velocity  comes from phase shift of pulse in cavity (averaged on round trip time  D. Jones, et al. Science, 288, 635, Apr. 28, 2000 

Future directions are wide open Optical frequency metrology: Ultrastable optical frequency synthesizer/network Optical atomic clock Ultrafast lasers for precision atomic & molecular spectroscopy Tests of fundamental physical principles Quantum Optics & Ultrafast physics Coherent control of quantum states Arbitrary pulse engineering, Precision control of ultrafast phenomenon Ultrafast laser with cold atoms: Ultrahigh resolution spectroscopy Coherent control of THz radiation Control of single cycle optical pulses: Extreme nonlinear optics, such as X-ray generation

How to make a highly reliable, stable, precise, accurate, reproducible comb photons? Comb frequency reference to narrow-linewidth atom transition directly!

How come ultra-wide band can resolve ultra-narrow linewidth?

coherent comb  …  … 822 nm 852 nm 895 nm 470 nm 822 nm Hyperfine structure of Cs atom

….. Comprehend by frequency domain T. H. Yoon, A. Marian, J. L. Hall, and J. Ye, Phys. Rev. A 63, (2001).

Comprehend by time domain  r.t   t E(t) 

What’s the next step?

Example: CW Ramsey Fringes Atomic beam Light beam PRL 94 (2005)

frequency coherently control a. Quantum beats   ae -iwat aa  be -iwbt bb  ce -iwct cc Be prepared by coherently pump with different frequencies 

EIT  

Cs-ionization rate controlling? coherent comb   nm Hyperfine structure of Cs atom S8 2/1 8S P7 Linewidth:1.5 MHz nm MHz MHz MHz 7P 3/2 : nm 7P 1/2 : nm nm 895nm 2/1 6S S6 P6 3   JIf 4   JIf 603 MHz 2 / 1 6P 2/3 6P 2   JIf 5  JIf MHz 30 nm

Controlling ultracold molecular vibrations?

K 2 photo-dissociation channels controlling? Controlling ultracold molecular vibrations? Control of molecular vibration

Long term possibilities and collaborating –Quantum control photons quantum information science nonlinear optics quantum optics Pulse engineering THz radiation controlling –Quantum control molecules Chemical dynamics/chemical reaction –Quantum control cool atoms Atoms in MOT (magnetic-optical trap)/optical lattice BEC

量子控制實驗室 中研院 原子分子研究所 331 實驗室

光頻率梳雷射於 2000 年研發成功  2005 即獲得諾貝爾獎 實驗室未來的方向為利用光梳雷射進行 各種量子干涉之觀察與控制，如︰ – 同調激發原子，觀察波函數量子干涉 – 光梳與原子交互作用，進行量子光學實驗 – 與化學動力學專家合作進行各種分子量子態 的控制

來我們實驗室你可以獲得以下的訓練 雷射物理 –( CW and pulse ，我們常須自己改雷射規格 ) 電子電路 –( 我們必須自製回授控制線路，溫控器，穩定電流源等 ) 光電元件 –( 我們常自製光電元件，如光偵測器，電光晶體等 ) 量子力學 高精密雷射光譜技術 歡迎您來我們實驗室參觀！