Spectrometer with variable beam power and shape

1. A spectrometer comprising:

at least one light source configured to emit at least one beam into a sample volume of an absorbing medium;

at least one detector configured to detect at least a portion of the at least one beam emitted by the light source;

a beam modification element; and

a controller configured to perform operations comprising:

determining, based on the detected portion, that an incident power on the at least one detector is outside of a linear response range of the at least one detector;

causing the beam modification element to selectively change a power intensity and/or a shape of the at least one beam to change the incident power on the at least one detector to within the linear response range.

2. The apparatus of claim 1 , wherein the absorbing medium comprises gas.

3. The apparatus of claim 1 , wherein the absorbing medium comprises liquid.

4. The apparatus of claim 1 further comprising:

a housing defining the sample volume, the housing defining a sample cell that comprises at least one of a multiple-pass configuration in which the light is reflected between one or more optically reflective mirrors while the light remains inside the sample cell, a multiple-pass configuration in which the light is refracted by one or more optical elements while the light remains inside the sample cell, a Herriot Cell, an off-axis optical resonator, a parabolic light collector, a spherical light collector, a White cell, an optical cavity, a hollow core light guide, or a single pass configuration in which the light is not being reflected while the light remains inside the sample cell.

5. The apparatus of claim 1 , wherein the sample volume forms part of an open path system.

6. The apparatus of claim 1 , wherein the beam modification element comprises an optical filter or an optical diffuser.

7. The apparatus of claim 1 , wherein the beam modification element comprises an optical lens.

8. The apparatus of claim 1 , wherein the beam modification element comprises a transmissive diffusor or a reflective diffusor.

9. The apparatus of claim 1 , wherein the beam modification element comprises a reflector with a selectively adjustable surface.

10. The apparatus of claim 1 , wherein the beam modification element comprises a liquid crystal optical element.

11. The apparatus of claim 1 , wherein the beam modification element comprises an adjustable aperture.

12. The apparatus of claim 1 , wherein the beam modification element comprises a tunable filter.

13. The apparatus of claim 12 , wherein the tunable filter comprises a thermal optical tuner.

14. The apparatus of claim 12 , wherein the tunable filter comprises a quantum well tuning element.

15. The apparatus of claim 1 , wherein the beam modification element comprises a filter wheel having two or more different optical filters that are selectively movable within the beam path.

16. The apparatus of claim 1 , wherein the beam modification element comprises a filter wedge.

17. The apparatus of claim 1 , wherein the beam modification element comprises at least one element selected from a group consisting of: saturable absorbers, optical fibers, spatial filters, waveguides, films made from at least one layer of dielectric material, films made from organic material which can be rotated, Bragg gratings, light valves, polarizers, light power actuators, transmissive optical elements with diffractive optical structures which alter the beam profile, transmissive optical elements with rough polishing, reflective optical elements with surface structure which causes scattering of an incident laser beam or alters the beam profile, diffractive optical elements, Fresnel type optical elements, films or optical elements made from hydrocarbon materials, or beam splitting devices.

18. The apparatus of claim 1 further comprising at least one actuation element that is coupled to at least one of (i) the at least one beam modification element, (ii) the at least one light source, or (iii) the at least one detector, that is and configured to selectively move a position and/or angle of the beam modification element along at least one axis.

19. A method comprising:

emitting, by at least one light source forming part of a spectrometer, at least one beam into a sample volume containing an absorbing medium;

detecting, by at least one detector, at least a portion of the beam emitted by the at least one light source;

determining, based on the detected portion that an incident power on the at least one detector is outside of a linear response range of the at least one detector; and

selectively changing, by at least one beam modification element a power intensity and/or a shape of the at least one beam to change the incident power on the at least one detector to within the linear response range.

20. A computer-implemented method comprising:

causing at least one light source forming part of a spectrometer to emit at least one beam into a sample volume comprising an absorbing medium;

receiving a signal from at least one detector characterizing detection of at least a portion of the beam emitted by the light source;

determining, based on the received signal, that an incident power on the at least one detector is outside of a linear response range of the at least one detector; and

causing at least one beam modification element to selectively change a power intensity and/or a shape of the at least one beam to change the incident power on the at least one detector to within the linear response range.