optmat.gas.crosschecks

Test the recommended models against dispersion data that no single fit uses.

Two kinds of measurement constrain dispersion without giving a refractive index:

• Phase-matching density ratios (Shelton 1986, 1990): two gases give the same electric-field-induced second-harmonic wave-vector mismatch at densities in the ratio rho_gas / rho_ref = Delta alpha_ref / Delta alpha_gas with Delta alpha = alpha(2 omega) - alpha(omega) (to first order in density). Each ratio ties the near-infrared dispersion of two gases together to about 0.1 %, which is a direct test of the neon, krypton and xenon models where they have no near-infrared data of their own. The fits use most of them (TC-96); here every one is compared.

• Group-delay dispersion (Borzsonyi et al. 2008): beta_2 = (lambda^3 / 2 pi c^2) d^2 n / d lambda^2 per metre at the measured state.

This module predicts each from the recommended models (models.registry) and returns the comparison.

Functions

group_delay_dispersions()	Compare every curated group-delay dispersion with the models.
phase_match_ratios()	Compare every curated phase-matching density ratio with the models.

Classes

Comparison(key, row, wavelength, measured, ...)

A measured value against the models' prediction.

class optmat.gas.crosschecks.Comparison(key, row, wavelength, measured, sigma, predicted)

Bases: object

A measured value against the models’ prediction.

Attributes:

keystr

The dataset.

rowstr

The row within it.

wavelengthfloat

The (fundamental) vacuum wavelength, m.

measuredfloat

The measured value.

sigmafloat

Its one-sigma uncertainty (NaN where none is stated).

predictedfloat

The models’ prediction.

property deviation: float

The relative deviation of the prediction from the measurement.

Returns:

float

predicted / measured - 1.

key: str

measured: float

predicted: float

row: str

sigma: float

wavelength: float

optmat.gas.crosschecks.group_delay_dispersions()

Compare every curated group-delay dispersion with the models.

Returns:

list of Comparison

One per row of every group_delay_dispersion dataset (fs^2/m at the dataset’s state), predicted by a centred second difference of the recommended model’s n in wavelength.

optmat.gas.crosschecks.phase_match_ratios()

Compare every curated phase-matching density ratio with the models.

Returns:

list of Comparison

One per row of every phase_match_density_ratio dataset whose two gases have recommended models; the prediction is the ratio of the models’ polarizability differences between the fundamental and its second harmonic.