Adaptive Optics J Mertz Boston University
n 1 n 2 Defocus Bad focus
Large peak-to-valley Defocus correction n 1 n 2 Bad focus
Small peak-to-valley Spherical aberration correction n 1 n 2 Good focus
? n 1 n 2
Work backwards Point source Guide star
Work backwards time reversal Point focus
Work backwards Phase measurement device Point source Guide star
Work backwards Shack-Hartmann sensor Point source Guide star
Shack-Hartmann sensor Lenticular screen
Shack-Hartmann sensor x Disadvantage: low resolution Advantage: high dynamic range
Shack-Hartmann sensor x Key advantage: achromatic!
Achromatic wavefront sensors Imagine Optic Shack-Hartmann sensor Low res; High dynamic range Phasics Modified-Hartmann sensor High res; Lower dynamic range
Phase reconstruction
feedback Shack-Hartmann sensor Point source Guide star
Phase control: Deformable mirrors Imagine Eyes Low resolution High dynamic range Boston Micromachines High resolution Lower dynamic range
Various AO strategies Sensor based Shack-Hartmann: Low coherence interferometry: CCD (Denk, 2006)
Intensity detector is insensitive to phase CCD
Low coherence interferometry (aka Digital holography) Reference beam CCD I 1
Low coherence interferometry (aka Digital holography) Reference beam CCD I 2
Low coherence interferometry (aka Digital holography) Reference beam CCD I 3
Low coherence interferometry (aka Digital holography) Reference beam CCD real I 1, I 2, I 3 a little math E complex
Reconstructed phase map
Numerical free space propagation Fresnel propagator z E 0 E 1 complex complex
Problem: phase wrapped 2p 0
Solution: phase unwrapping unwrapped wrapped 2p 0
Problem: wrapped, speckly, noisy,
Numerical free space propagation Fresnel propagator z E 0 E 1 complex complex
Numerical focusing E 0 E 1 =FT{E 0 }
Virtual Shack-Hartmann E 0 E 1 =FT{E 0 }
Virtual Shack-Hartmann Feierabend, Rueckel, Denk, OL 2004
Virtual Shack-Hartmann Feierabend, Rueckel, Denk, OL 2004
Virtual Shack-Hartmann Feierabend, Rueckel, Denk, OL 2004
Virtual Shack-Hartmann Feierabend, Rueckel, Denk, OL 2004
PNAS 2006 6 2PEF signal improvement
Various AO strategies Sensor based Shack-Hartmann: Low coherence interferometry: CCD (Denk, 2006) Image based Zonal: (Ji, Betzig, 2010) Modal: (Booth, Debarre, 2010)
Image-based zonal Ji, Betzig, Nat. Meth. 2010
Ji, Milkie, Betzig, NM 2010
Various AO strategies Sensor based Shack-Hartmann: Low coherence interferometry: CCD (Denk, 2006) Image based Zonal: (Ji, Betzig, 2010) Modal: (Booth, Debarre, 2010)
quality Image-based: modal Débarre, Booth & Wilson OE 2007 Define orthogonal modes piston Optimize modes sequentially Φ 0 Φ 0 -a Φ 0 +a optimum tip defocus tilt aberration Polytechnique LOB 2N+1 images required
Image-based modal correction (2PEF microscopy) Fixed mouse embryo Débarre et al (Opt Lett 2009)
Polytechnique LOB Adaptive optics for nonlinear microscopy Drosophila larva: third-harmonic / second-harmonic generation microscopy. THG uncorrected corrected SHG (muscles) Cf Olivier et al, Opt Lett 34, 2145 (2009) Better visibility of small structures Signal x2.5 - Extra-illumination needed: +150%
Uncorrected Dynamic adaptive optics for nonlinear microscopy Corrected THG imaging of a developing drosophila embryo Olivier et al, Opt Lett 34, 2145 (2009)
Adaptive optics for 2PEF-THG microscopy 2PEF and THG imaging of pollen grains Uncorrected Corrected Olivier, Débarre, Beaurepaire, Optics Letters 34, 2145 (2009) «Dynamic aberration correction for multiharmonic microscopy» 2PEF THG Applied phase (rad)
Problem: aberrations mirror mirror tissue
Signal + Background Two-photon microscopy
Problem: aberrations mirror mirror tissue Solution: Adaptive optics deformable mirror actuators tissue
Signal + Background Background
Differential aberration imaging (fake adaptive optics) Signal + Background Background Signal
DAI Standard TPEF ~1ms Line-by-line DAI Aberrations off Aberrations on
Standard TPEF
Differential aberration TPEF
Blood vessels (200 um deep) Focal modulation microscopy (FMM) ( 1MHz modulation with AOM and lock-in detection) Chong et. al., BOE 2010
Where is AO going?
Focusing through scattering media SLM CCD Vellekoop, Mosk, Opt. Lett. 2007 Gigan, Yang, Silberberg