First year talk Mark Zentile The Slow-Light Effect First year talk Mark Zentile

1st year talk, Mark Zentile Project Members Lee Weller Charles Adams Ifan Hughes 17/04/2017 1st year talk, Mark Zentile

1st year talk Mark Zentile Outline Slow-light: What is slow-light? What conditions are needed to see it? What are the applications? Phase shift and absorption from the electric susceptibility. Transmission spectra to extract key parameters for the model. Using the our model for the electric susceptibility with Fourier analysis to model pulse propagation. Experimental method and examples of data with theoretical predictions. 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Outline Future outlook: Introduce the Faraday effect. Use a Faraday signal to make a tuneable laser lock over ± 20 GHz detuning. Harness the slow-light Faraday effect to make an optical switch. 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile What is ‘Slow-Light’?       17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile What is ‘Slow-Light’? 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Slow-light with EIT 17/04/2017 1st year talk Mark Zentile

Better interferometers 17/04/2017 1st year talk Mark Zentile

Image rotation  Image coding 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Optical Delay Line 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Optical Switch 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Outline Slow-light: What is slow-light? What conditions are needed to see it? What are the applications? Phase shift and absorption from the electric susceptibility. Transmission spectra to extract key parameters for the model. Using the our model for the electric susceptibility with Fourier analysis to model pulse propagation. Experimental method and examples of data with theoretical predictions. 17/04/2017 1st year talk Mark Zentile

Complex refractive index   ABSORPTION DISPERSION 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Transmission Spectra     17/04/2017 1st year talk Mark Zentile

The model for the electric susceptibility Our model has been developed over many years: Result of solving the optical Bloch equations for a two level atom. Accurate up to ~ 120oC Includes: absolute linestrengths Doppler broadening Temperature dependent number density. Siddons et al. J. Phys. B: At. Mol. Opt. Phys. 41 (2008) 155004 17/04/2017 1st year talk Mark Zentile

The model for the electric susceptibility Inclusion of self-broadening: Accurate up to ~ 360oC Includes: absolute linestrengths Doppler broadening Temperature dependent number density. Self-broadening for binary-collision approximation Weller et al. J. Phys. B: At. Mol. Opt. Phys. 44 (2011) 195006 17/04/2017 1st year talk Mark Zentile

The model for the electric susceptibility Inclusion of magnetic field: Tested up to 0.6 T Includes: absolute linestrengths Doppler broadening Temperature dependent number density. Self-broadening for binary-collision approximation Magnetic energy level shift. Weller et al. J. Phys. B: At. Mol. Opt. Phys. 45 (2012) 055001 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Outline Slow-light: What is slow-light? What conditions are needed to see it? What are the applications? Phase shift and absorption from the electric susceptibility. Transmission spectra to extract key parameters for the model. Using the our model for the electric susceptibility with Fourier analysis to model pulse propagation. Experimental method and examples of data with theoretical predictions. 17/04/2017 1st year talk Mark Zentile

Transmission: Extracting parameters We want to use transmission spectra to measure experimental parameters. Transmission  χ(ω)  dispersion  slow-light theory. Why model transmission spectra? Can’t we just use Kramers-Kronig? Yes, but... 17/04/2017 1st year talk Mark Zentile

Transmission: Extracting parameters Rubidium 75 mm long cell, room temperature. Excellent agreement. One fit parameter: Temp = (20.70 ± 0.13) oC 17/04/2017 1st year talk Mark Zentile

Transmission: Extracting parameters 2 mm long 98.2% 87Rb cell: 3 fit parameters: Temp = (90.2 ± 0.1)oC Lorentzian FWHM = 2π ∙ (165 ± 1) MHz Very large! => Buffer gas. Ratio of 87Rb to 85Rb = 0.982 ± 0.009 17/04/2017 1st year talk Mark Zentile

Transmission: Extracting parameters 2 mm long 87Rb cell (high temp): 2 fit parameters: Temp = (182.1 ± 0.4)oC Lorentzian FWHM = 2π ∙ (170 ± 4) MHz Very large! => Buffer gas. 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Outline Slow-light: What is slow-light? What conditions are needed to see it? What are the applications? Phase shift and absorption from the electric susceptibility. Transmission spectra to extract key parameters for the model. Using the our model for the electric susceptibility with Fourier analysis to model pulse propagation. Experimental method and examples of data with theoretical predictions. 17/04/2017 1st year talk Mark Zentile

Fourier Method for pulse propagation Electric susceptibility model is designed for monochromatic continuous wave light. Pulses are clearly not monochromatic continuous wave light! Solution: Use a Fourier transform to write the pulse in terms of continuous wave light. 17/04/2017 1st year talk Mark Zentile

Fourier Method for pulse propagation Fourier decomposition: 17/04/2017 1st year talk Mark Zentile

Good conditions for slow-light? Rubidium at natural abundance 98.2% 87Rb 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Fast-Light 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Outline Slow-light: What is slow-light? What conditions are needed to see it? What are the applications? Phase shift and absorption from the electric susceptibility. Transmission spectra to extract key parameters for the model. Using the our model for the electric susceptibility with Fourier analysis to model pulse propagation. Experimental method and examples of data with theoretical predictions. 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Experimental Setup 17/04/2017 1st year talk Mark Zentile

Advantages/disadvantages of FPD Works over one shot Slow rise time => poor resolution Need relatively intense pulses => may not be weak probe. Picture from http://www.eotech.com/product/14/2GHz_Amplified/ 17/04/2017 1st year talk Mark Zentile

Advantages/disadvantages of SPCM Slightly better timing resolution. Works for much less Intense pulses. Must build a pulse profile over many repetitions. Picture from http://excelitas.com/downloads/DTS_SPCM_AQRH.pdf 17/04/2017 1st year talk Mark Zentile

Preliminary experimental data (FPD) Group refractive index of ~1000 17/04/2017 1st year talk Mark Zentile

Experimental data with theory (FPD) 87Rb cell. Laser locked by polarization spectroscopy. Carrier frequency on resonant with 85Rb D1 Fg=2  Fe=2,3 transition frequency. Reference Pink = Measured output Red Dashed = Theory 17/04/2017 1st year talk Mark Zentile

Experimental data with theory (SPCM) Reference Rb natural abundance cell. Counted over a relatively short time Red = Measured output Black Dashed = Theory 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Outline Future outlook: Introduce the Faraday effect. Use a Faraday signal to make a tuneable laser lock over ± 20 GHz detuning. Harness the slow-light Faraday effect to make an optical switch. 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile The Faraday Effect Linearly polarized light can be constructed from a circularly polarized basis. 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile The Faraday Effect A magnetic field breaks the degeneracy for right and left circular components 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile The Faraday Effect Have already seen that the model can accurately predict Faraday rotation: Weller et al. J. Phys. B: At. Mol. Opt. Phys. 45 (2012) 055001 17/04/2017 1st year talk Mark Zentile

A Faraday signal as a laser lock Take inspiration from this paper. Locking off-resonance Marchant, A. L., Händel, S., Wiles, T. P., Hopkins, S. A., Adams, C. S., & Cornish, S. L. (2011). Optics letters, 36, 64-6. 17/04/2017 1st year talk Mark Zentile

A Faraday signal as a laser lock Can use our 1 mm long cell placed in a permanent magnet to achieve high magnetic fields We will be able to lock on-resonance as well as off. 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Outline Future outlook: Introduce the Faraday effect. Use a Faraday signal to make a tuneable laser lock over ± 20 GHz detuning. Harness the slow-light Faraday effect to make an optical switch. 17/04/2017 1st year talk Mark Zentile

The Slow-light Faraday effect Large rotation with little absorption Siddons, P., Bell, N., Cai, Y., Adams, C. S., & Hughes, I. G. (2009). Nature Photonics, 3, 225 17/04/2017 1st year talk Mark Zentile

Use optical pumping to control rotation Can also cause a rotation by having an unbalanced distribution in the populations of the Zeeman sub-levels. 17/04/2017 1st year talk Mark Zentile

Use optical pumping to control rotation 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Summary Seen what slow-light is and what its applications are. Phase shift and absorption from the electric susceptibility. How we use transmission spectra to measure parameters for the model. Seen how to model pulse propagation with the Fourier analysis, once χ in known. Experimental method and examples of data with theoretical predictions. 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Summary Explained the Faraday effect. Want to use a Faraday signal to make a tuneable laser lock. Harness the slow-light Faraday effect to make an optical switch. 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile End Thanks for listening. 17/04/2017 1st year talk Mark Zentile

Fit with magnetic field 17/04/2017 1st year talk Mark Zentile

Controlled Faraday rotation Siddons, P., Adams, C. S., & Hughes, I. G. (2010). Physical Review A, 81, 043838 17/04/2017 1st year talk Mark Zentile

Pump-Probe energy level diagram 17/04/2017 1st year talk Mark Zentile

1st year talk Mark Zentile Jitter in arrival time FPD shows a ‘jitter’ in the arrival time and peak height. This will broaden a photon counted pulse! 17/04/2017 1st year talk Mark Zentile

Simulating photon counting pulses 17/04/2017 1st year talk Mark Zentile