Interferometric determination of a transfer function of a device under test
A method of evaluating a device under test (DUT) includes detecting four interferograms of the DUT including two orthogonal detections and two orthogonal input polarizations, performing a Hilbert transformation to obtain transfer functions of the DUT on the basis of the detected interferograms, performing an Inverse Fourier transformation on the transfer functions of the DUT to get an impulse response matrix IR of the DUT, and determining impulse response eigenvalues of the DUT on the basis of the impulse response matrix of the DUT.
1. A method of evaluating a device under test (DUT), comprising:
detecting four interferograms of the DUT including two orthogonal detections and two orthogonal input polarizations
performing a Hilbert transformation to obtain transfer functions of the DUT on the basis of the detected interferograms,
performing an Inverse Fourier transformation on the transfer functions of the DUT to get an impulse response matrix IR of the DUT, and
determining impulse response eigenvalues of the DUT on the basis of the impulse response matrix of the DUT.
2. The method of claim 1 , further comprising: determining impulse response amplitude eigenvalues of the impulse response matrix by solving an eigenvalue problem in time domain with a matrix product according to the following scheme:
IR
T
*
IR
·
v
ρ
ir
=
ev
ir
·
v
ρ
ir
det
(
IR
T
*
IR
-
ev
ir
·
E
)
=
0
with envelope eigenvalues eν ir and the eigenvectors {right arrow over (ν)} ir .
3. A software program or product, encoded on a computer readable medium, with instructions for executing the method of claim 1 when run on a data processing system.
4. An apparatus for evaluating a device under test (DUT), comprising:
an interferometer for detecting four interferograms of the DUT including two orthogonal detections and two orthogonal input polarizations, and
an evaluation unit for performing a Hilbert transformation to obtain transfer functions of the DUT on the basis of the detected interferograms, and for performing an Inverse Fourier transformation on the transfer functions of the DUT to get an impulse response matrix IR of the DUT, and for determining impulse response eigenvalues of the DUT on the basis of the impulse response matrix of the DUT.
5. The apparatus of claim 4 ,
wherein the evaluation unit determines impulse response amplitude eigenvalues of the impulse response matrix by solving an eigenvalue problem in time domain with a matrix product according to the following scheme:
IR
T
*
IR
·
v
ρ
ir
=
ev
ir
·
v
ρ
ir
det
(
IR
T
*
IR
-
ev
ir
·
E
)
=
0
with envelope eigenvalues eν ir and the eigenvectors {right arrow over (ν)} ir .