1. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Amplitude and Phase Detection J-C Lehureau Thales Research and Technology

2. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Frequency of electronic components Ge Si GaAs WDM

3. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Heterodyne Detection X  X² Y² |s+p|²-|s-p|² Radio signal Optical interference

4. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Coherent-incoherent interference

5. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Power detection  int =  N  p  shot =  N  tot =   int 2 +  shot 2 =  N *(1+ p) N photons p photon 

6. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Power detection  tot =  N *(1+ p) is a quantum limited detector if: shot noise >>additive noise Example of microbolometer: NETD=50 mK on 2500µm² NEP =.75 nW NEW =30 pJ = 10 10 photons The pump must be nearly 1 Joule per pixel!! Example of CMOS addressed photodiode: reading noise = 1000 electrons N >> 1 million photons = 0.01 pJ

7. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Amplitude and phase detection signal pump XOR

8. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 t Physical measurement Signal processing + wavefront sensor Image Field measurements Synthesis Propagation model Phase calibration Laser source speckle field Phase detection & image reconstruction

9. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Short range experimentation Digital holography enables wavefront estimation on a great number of pixels –12 bits 512x512 CCD frames Synthesis by means of object rotation –overlapping holograms increases resolution –aberration correction by calculus Z=50m

10. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Thermal source A mode is defined by geometrical extent and time-bandwidth: the population of a mode is p= 1/(exp(h /kT - 1) p=1% at peak

11. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 An example of phase detection incoherent holography FFT CCD Color filter QuadratorIntegrator laser At T=3300K, =900nm, P photon =1% For each shot: S/N= -20dB After 10000 shotsS/N= +20dB

12. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 signal pump Faint correlation Let us normalize the pump to unity: each output gives a signal: s1=s2=  p cos  where p is the population of a mode  is a random phase The correlation of the two outputs: S= s1*s2 = p is to be compared to the unity noise One needs N>>1/p² samples to overcome the noise

13. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 An astronomic example 2 telescopes make an observation at 100 light-years The resolution of each is 1µRd i.e. 10 a.u./pixel is chosen such that p~  ( =5 peak ) Cross section of the star is 1/1 000 000 of a pixel Light from a planet is 1/1 000 000 000 of the star At 1000 billion samples/second: the star generates correlation within 1s the planet can be seen within 10000 days

14. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Image formation by a rotating linear antenna The N>>1/p² rules generates a dramatic loss in information capacity; this can be compensated by generating more correlation function than the number of detectors

15. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 %decoded %erreur capacity Maximum entropy of low S/N The capacity of a channel is increased by erasing samples below a threshold

16. THALES RESEARCH & TECHNOLOGY FRANCE This document and any data included are the property of THALES. They cannot be reproduced, disclosed or used without THALES' prior written approval. ©THALES 2002. Modèle trtco V 5.1.0 Conclusions Modern infrared detectors (InP, QWIP) have a bandwidth which allows the analysis of a significant part of optical spectrum. Optical heterodyne power detection has the same theoretical limit as quantum limited detector but will find application only where detailed analysis of optical spectrum is needed. Heterodyne detector is cheap: multichannel structure is possible Phase and amplitude detection generates a non material link between remote telescopes. The number of correlation function varies as the square of detecting sites. Computer correlation allow image formation with “a posteriori” phase correction. There is a need for information link/storage in the peta/exa byte range