Releases · polyanskiy/co2amp

Expanded vibrational-level model.
Improved optical pumping model.

Added Doppler broadening to transition linewidth calculations (effective linewidth / dephasing treatment).
Revisited lab-frame vs pulse-frame time overlap handling to improve robustness and consistency across layouts.
Optimized output generation, re-introducing complete pulse/beam saves for closely spaced active-medium sections.
Improved the polarization update algorithm using an exact linear+drive step (more stable/consistent at larger detunings and shorter Δt.
Clarified and corrected phase sign conventions in the field definition and FFT/IFFT routines (consistent frequency-axis orientation and shifts).
Code clean-up and refactoring (readability, maintainability, and minor internal simplifications).
Updated documentation to reflect the above changes and unify notation/conventions.

Added support for vibrational relaxation and pumping during pulse amplification.
The previous assumption that these processes are negligible on the pulse timescale has been removed. This update is particularly relevant for the amplification of relatively long (e.g., chirped) pulses in high-CO₂-content amplifiers, where vibrational processes during the pulse amplification may contribute significantly.
Enhanced optical pumping model.
- Added pumping at 1.44 µm (3ν₃ overtone), ~2.0 µm (201, 121, 041 combination bands), and ~2.2 µm (2ν₃ overtone).
- Introduced explicit specification of the pumping level (pump_level: 001 / 021 / 041 / 002 / 003).
- Updated pump-beam specification to match the format used for the amplified pulse: pump pulse energy plus independent spatial and temporal profiles. Standard pulse/beam shapes (Gaussian, flattop, etc.) are now supported.
Refactored lab-time-frame handling.
- Standardized variable naming (m, m0).
- Adopted consistent use of time moments centered on each time tick.
- Implemented precomputation of the discharge-pump energy distribution for the entire simulation time, enabling multi-threaded calculations.
Added configurable save and solve intervals.
Users can now specify time intervals for saving pumping dynamics and re-solving Boltzmann equations via the save_interval and solve_interval options in the amplifier-section YAML configuration files.
Improved phase handling.
Implemented phase unwrapping to ensure relevant output information.
Improved handling of population distribution.
Replaced the statistical model for distributing vibrational energy within polyads of coupled levels with a more accurate Boltzmann-based distribution model.

Added a rudimentary support for optical pumping through 3ν3 (assuming each 1.43 um photon excites three molecules to 001)

Finalized support for laser transitions around 4 μm

Refactoring of Molecular Spectroscopy and Amplification Code
- Transition data is now loaded from HITRAN .par files, replacing hard-coded molecular constants.
- Sub-levels of vibrational levels coupled with laser-active levels, but not directly involved in laser transitions, are now accounted for.
- Improved accuracy in tracking population distributions across vibrational sub-levels.
- Added support for Oxygen-17-containing isotopologues of CO₂.
- Increased the number of rotational levels considered, now including quantum numbers J up to 79.
- Initiated support for 4-micron transitions (further work needed to enable non-equilibrium population distributions within a vibrational mode by adopting a thermalization time parameter).
Enhanced Terminal Output
- Improved Debugging Level 1 output, with more useful information and better organization of terminal messages.
Program Name Update
- Removed "2020" from the program name. Backward compatibility is maintained with .co2 files created by co2amp 2020.
Documentation Update
- Expanded and updated documentation to reflect the new changes and features.