Optical pulse source, optical system for rydberg excitation, and method for forming optical pulses - Patents.com

Abstract

1. An optical pulse source (100) comprising: a first laser (110) configured to output laser light at a first wavelength; a second laser (112) configured to output laser light at a second wavelength different from the first wavelength; an optical modulation device (120) configured to apply amplitude modulation to a first laser light of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse; an optical amplification device (130) configured to amplify the first laser light pulse and a second laser light of the laser light at the first wavelength or the laser light at the second wavelength; and an optical frequency conversion device (140) configured to perform optical frequency conversion using the first laser light pulse and the second laser light of the laser light at the first wavelength or the laser light at the second wavelength to form an output laser light pulse at a third wavelength shorter than the first wavelength and the second wavelength.

Description

[Technical field]

[0001] The present invention relates to an optical pulse source and a method for generating optical pulses.The present invention further relates to an optical system for Rydberg excitation. [Background technology]

[0002] It is known that the generation of light pulses at wavelengths where a laser cannot directly generate laser light, e.g., ultraviolet (UV) wavelengths, can be accomplished by generating continuous wave (cw) laser light at high optical power, then frequency converting the high power cw laser light to the desired output wavelength, and amplitude modulating the frequency converted cw laser light to form output light pulses with lower peak optical power. US Pat. No. 5,399,433 describes an alternative approach for the generation of deep UV laser pulses in which a directly modulated semiconductor laser is used to generate laser pulses that are then amplitude and frequency modulated to generate laser pulses at about 198 nm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2007 / 064749 Summary of the Invention [Problem to be solved by the invention]

[0004] An optical pulse source, an optical system for Rydberg excitation, and a method for forming an optical pulse are provided. [Means for solving the problem]

[0005] A first aspect provides an optical pulse source comprising a first laser, a second laser, an optical modulator, an optical amplifier, and an optical frequency converter. The first laser is configured to output laser light at a first wavelength. The second laser is configured to output laser light at a second wavelength different from the first wavelength. The optical modulator is configured to apply amplitude modulation to a first one of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse. The optical amplifier is configured to amplify the first laser light pulse and the second one of the laser light at the first wavelength or the laser light at the second wavelength. The optical frequency converter is configured to perform optical frequency conversion using the first laser light pulse and the second one of the laser light at the first wavelength or the laser light at the second wavelength to form an output laser light pulse at a third wavelength. The third wavelength is shorter than the first wavelength and the second wavelength.

[0006] By forming the first laser light pulses prior to optical frequency conversion, the optical pulse source may enable more power-efficient output pulse generation than a system that forms output pulses from cw laser light after optical frequency conversion to a desired third (output) wavelength. Thus, the optical pulse source may form output pulses of a desired pulse peak power using lower average optical power than would be required for a system that forms output pulses from cw laser light after optical frequency conversion. Advantageously, pulse-to-pulse noise is efficiently suppressed during optical frequency conversion of the first laser light pulses into output laser light pulses.

[0007] In one embodiment, the optical modulation device comprises a first optical modulator configured to apply amplitude modulation to one of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse. The use of an external optical modulator allows a desired shape of amplitude modulation to be applied to form a desired shape of the first laser light pulse.

[0008] In one embodiment, the optical modulation device further comprises a second optical modulator. The first optical modulator is configured to apply amplitude modulation to the laser light at the first wavelength to form a first laser light pulse at the first wavelength. The second optical modulator is configured to apply amplitude modulation to the laser light at the second wavelength to form a second laser light pulse at the second wavelength. The use of an external optical modulator allows a desired shape of amplitude modulation to be applied to the laser light to form a desired shape of the first and second laser light pulses.

[0009] One advantage of modulating the laser light at the first and / or second wavelengths using a modulation device to form the laser light pulses is that a wide range of modulation profiles can be applied to the formed laser pulses. The pulse modulation can be optimized to compensate for downstream shape disturbances of the laser light pulses, for example, introduced by the optical amplifier and / or optical frequency converter. Optical amplifiers typically have a non-uniform gain response in the time domain caused by inversion depletion in the optical amplifier gain medium that occurs as the pulse propagates through the gain medium. By decreasing the pulse intensity at the leading edge of the pulse relative to the trailing edge of the pulse, the decreasing amplification over the pulse can be compensated for. In conventional systems where the laser light pulses are delivered directly from the first and second lasers, for example by directly modulated semiconductor lasers, the modulation of the lasers, and therefore the pulse modulation capabilities, are limited and insufficient to compensate for these shape disturbances.

[0010] In one embodiment, the optical amplification apparatus comprises a first optical amplifier configured to amplify a first laser light pulse and a second optical amplifier configured to amplify a second laser light pulse.

[0011] In one embodiment, the optical amplifier is configured to be continuously pumped. Continuously pumping the optical amplifier advantageously allows energy to build up in the optical amplifier between pulses, which allows the optical amplifier to amplify the first laser light pulse to have a high pulse peak power while pumping the optical amplifier to amplify to a relatively low average power.

[0012] In one embodiment, the optical pulse source further comprises an output pulse control device comprising a photodetector and a controller. The photodetector is configured to detect a pulse shape of the laser light pulse and generate an output signal indicative of the detected pulse shape. The controller comprises an interface circuit, at least one processor, and a memory comprising instructions executable by the processor, the controller operative to: receive an output signal indicative of the detected pulse shape from the photodetector; determine a difference between the detected pulse shape and a target pulse shape; and determine a compensatory pulse shape for the first laser light pulse. The compensatory pulse shape is configured to at least partially compensate for the difference between the detected pulse shape and the target pulse shape. The controller operative to generate at least one drive signal for the optical modulation device. The at least one drive signal is configured to cause the optical modulation device to apply amplitude modulation to form the first laser light pulse having the compensatory pulse shape.

[0013] Forming a first laser light pulse having a compensatory pulse shape can enable the optical pulse source to compensate for pulse shape disturbances introduced by an optical amplification device and / or an optical frequency conversion device, which may advantageously enable the optical pulse source to form an output laser light pulse having a target pulse shape that is independent of such pulse shape disturbances.

[0014] In one embodiment, the optical modulation device comprises a first optical modulator and a second optical modulator. The first optical modulator is configured to apply amplitude modulation to the laser light at a first wavelength to form a first laser light pulse at the first wavelength, and the second optical modulator is configured to apply amplitude modulation to the laser light at a second wavelength to form a second laser light pulse at the second wavelength. The controller is operative to determine at least one of a first compensation pulse shape for the first laser light pulse or a second compensation pulse shape for the second laser light pulse. The at least one drive signal is configured to cause at least one of the first optical modulator to apply amplitude modulation to form a first laser light pulse having the first compensation pulse shape or the second optical modulator to apply amplitude modulation to form a second laser light pulse having the second compensation pulse shape.

[0015] Forming the first and second laser light pulses having compensatory pulse shapes can enable the optical pulse source to compensate for pulse shape disturbances introduced by the optical amplification device and / or the optical frequency conversion device, which may advantageously enable the optical pulse source to form output laser light pulses having a target pulse shape that is independent of such pulse shape disturbances.

[0016] In one embodiment, the optical detector is configured to detect the pulse shape of the laser light pulses output from the optical frequency conversion device. In one embodiment, the optical detector is configured to detect the pulse shape of the laser light pulses output from the optical amplifier device.

[0017] In one embodiment, the target pulse shape is one of a rectangular pulse or a Gaussian pulse. In one embodiment, the at least one drive signal is further configured to cause the optical modulator to apply amplitude modulation to form first laser light pulses having a pulse duration up to 1 μs and a pulse repetition rate within the range of 0.1 kHz to 1 MHz.

[0018] In one embodiment, the first laser light pulse has a pulse duration of up to 500 ns. In one embodiment, the first laser light pulse has a pulse duration in the range 1 ns to 500 ns.

[0019] In one embodiment, the optical modulator is further configured to apply a phase modulation to one of the laser light at the first wavelength or the laser light at the second wavelength. The controller is further operative to generate at least one drive signal configured to determine a phase offset for the first laser light pulse and to cause the optical modulator to additionally apply a phase modulation to one of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse with a phase offset between subsequent laser light pulses. This may enable the optical pulse source to form output laser light pulses having a constant phase offset between subsequent pulses.

[0020] In one embodiment, the optical modulation device comprises a first optical modulator and a second optical modulator. The first optical modulator is configured to apply amplitude modulation to the laser light at the first wavelength to form a first laser light pulse at the first wavelength, and the second optical modulator is configured to apply amplitude modulation to the laser light at the second wavelength to form a second laser light pulse at the second wavelength. The first optical modulator is further configured to apply phase modulation to the laser light at the first wavelength, and the second optical modulator is further configured to apply phase modulation to the laser light at the second wavelength. The controller is further operative to determine a phase offset for the first laser light pulse and the second laser light pulse. The controller is further operative to generate at least one drive signal configured to cause the first optical modulator to additionally apply a phase modulation to the first laser light at the first wavelength to form a first laser light pulse with a phase offset between subsequent first laser light pulses and the second optical modulator to additionally apply a phase modulation to the laser light at the second wavelength to form a second laser light pulse with a phase offset between subsequent second laser light pulses. This may enable the optical pulse source to form output laser light pulses having a constant phase offset between subsequent pulses.

[0021] In one embodiment, the first optical modulator and / or the second optical modulator comprise an acousto-optic modulator (AOM), a Mach-Zehnder electro-optic modulator (MZM-EOM), or a semiconductor optical amplifier (SOA). For example, an RF signal generated by an RF signal generator can then be provided as a drive signal to the optical modulator, which drives the optical modulator to intensity modulate the cw optical signal to form an optical pulse. By introducing an appropriate intensity / power envelope to the RF drive signal, the shape of the generated pulse can be configured to at least partially compensate for the non-uniform gain response by the downstream optical amplifier and / or optical frequency conversion device. In one embodiment, the RF signal amplitude envelope has a leading edge and a trailing edge, and the amplitude of the RF signal increases between the leading edge and the trailing edge to provide that the pulse generated by the modulator has an asymmetric shape.

[0022] In one embodiment, the optical frequency conversion device is configured to perform optical frequency conversion by second harmonic generation (SHG) and one of sum frequency generation (SFG) or difference frequency generation (DFG). The use of SHG in the optical frequency generation device advantageously allows efficient suppression of inter-pulse noise in addition to frequency doubling. SHG is intensity dependent, so the higher power portion of the first laser light pulse is more efficiently frequency converted and the lower power inter-pulse noise is efficiently suppressed.

[0023] In one embodiment, the optical frequency conversion device comprises an SFG device and an SHG device. The SFG device is configured to perform sum frequency generation using a first laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a sum frequency laser light pulse. The SHG device is configured to perform frequency doubling of the sum frequency laser light pulse to form an output laser light pulse. Advantageously, the SFG device is capable of performing sum frequency generation to form a sum frequency laser light pulse regardless of whether the other of the laser light at the first wavelength or the laser light at the second wavelength comprises a cw laser light or a second laser light pulse.

[0024] In one embodiment, the first wavelength is within a first wavelength range of the range 1050 nm to 1110 nm or the range 1535 nm to 1590 nm, the second wavelength is within a second wavelength range of the range 1050 nm to 1110 nm or the range 1535 nm to 1590 nm, and the output laser light pulses have a wavelength of one of 317 nm or 318 nm. The light pulse source may advantageously provide output laser light pulses at a wavelength suitable for Rydberg excitation of strontium or cesium atoms.

[0025] In one embodiment, the first wavelength is a first wavelength value of 1064 nm or 1560 nm, the second wavelength is a second wavelength value of 1064 nm or 1560 nm, and the output laser light pulses have a wavelength of 317 nm. The light pulse source may advantageously provide output laser light pulses at a wavelength suitable for Rydberg excitation of strontium atoms.

[0026] In one embodiment, the first wavelength is a first wavelength value of 1072.8 nm or 1550 nm, the second wavelength is a second wavelength value of 1072.8 nm or 1550 nm, and the output laser light pulses have a wavelength of 317 nm. The light pulse source may advantageously provide output laser light pulses at a wavelength suitable for Rydberg excitation of strontium atoms.

[0027] In one embodiment, the first wavelength is a first wavelength value of 1078.6 nm or 1550 nm, the second wavelength is a second wavelength value of 1078.6 nm or 1550 nm, and the output laser light pulses have a wavelength of 318 nm. The light pulse source may advantageously provide output laser light pulses at a wavelength suitable for Rydberg excitation of cesium atoms.

[0028] In one embodiment, the optical frequency conversion device comprises a first SHG device, a SFG device, and a second SHG device. The first SHG device is configured to frequency double the first laser light pulse to form a frequency doubled laser light pulse. The SFG device is configured to perform sum frequency generation using the frequency doubled laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a sum frequency laser light pulse. The second SHG device is configured to perform frequency doubling of the sum frequency laser light pulse to form an output laser light pulse. Advantageously, the SFG device is capable of performing sum frequency generation to form a sum frequency laser light pulse, regardless of whether the other of the laser light at the first wavelength or the laser light at the second wavelength comprises a cw laser light or a second laser light pulse.

[0029] In one embodiment, the first wavelength is a first wavelength value of 1566 nm or 1966 nm, the second wavelength is a second wavelength value of 1566 nm or 1966 nm, and the output laser light pulses have a wavelength of 302 nm. The light pulse source may advantageously provide output laser light pulses at a wavelength suitable for Rydberg excitation of ytterbium atoms.

[0030] In one embodiment, the first wavelength is a first wavelength value of 1559 nm or 1970 nm, the second wavelength is a second wavelength value of 1559 nm or 1970 nm, and the output laser light pulses have a wavelength of 302 nm. The light pulse source may advantageously provide output laser light pulses at a wavelength suitable for Rydberg excitation of ytterbium atoms.

[0031] In one embodiment, the optical frequency conversion device comprises a first SHG device, a DFG device, and a second SHG device. The first SHG device is configured to frequency double the first laser light pulse to form a frequency doubled laser light pulse. The DFG device is configured to perform difference frequency generation using the frequency doubled laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a difference frequency laser light pulse. The second SHG device is configured to perform frequency doubling of the difference frequency laser light pulse to form an output laser light pulse. Advantageously, the DFG device is capable of performing difference frequency generation to form a difference frequency laser light pulse, regardless of whether the other of the laser light at the first wavelength or the laser light at the second wavelength comprises a cw laser light or a second laser light pulse.

[0032] In one embodiment, the first wavelength is a first wavelength value of 1560 nm or 1092 nm, the second wavelength is a second wavelength value of 1560 nm or 1092 nm, and the output laser light pulses have a wavelength of 420 nm. The light pulse source may advantageously provide output laser light pulses at a wavelength suitable for Rydberg excitation of rubidium atoms.

[0033] Corresponding embodiments and advantages also apply to the optical system for Rydberg pumping and the method for forming optical pulses described below. A second aspect provides an optical system for Rydberg pumping, the optical system comprising an optical pulse source and a pumping chamber. The optical pulse source comprises a first laser, a second laser, an optical modulator, an optical amplifier, and an optical frequency converter. The first laser is configured to output laser light at a first wavelength. The second laser is configured to output laser light at a second wavelength different from the first wavelength. The optical modulator is configured to apply amplitude modulation to a first one of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse. The optical amplifier is configured to amplify the first laser light pulse and the second one of the laser light at the first wavelength or the laser light at the second wavelength. The optical frequency converter is configured to perform optical frequency conversion using the first laser light pulse and the second one of the laser light at the first wavelength or the laser light at the second wavelength to form an output laser light pulse at a third wavelength. The third wavelength is shorter than the first wavelength and the second wavelength.

[0034] A third aspect provides a method of generating laser light pulses. The method comprises generating laser light at a first wavelength and generating laser light at a second wavelength different from the first wavelength. The method further comprises applying amplitude modulation to a first one of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse. The method further comprises amplifying the first laser light pulse and a second one of the laser light at the first wavelength or the laser light at the second wavelength. The method further comprises performing optical frequency conversion using the first laser light pulse and the second one of the laser light at the first wavelength or the laser light at the second wavelength to form an output laser light pulse at a third wavelength shorter than the first wavelength and the second wavelength.

[0035] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0036] [Figure 1] 1 is a block diagram illustrating an embodiment of an optical pulse source. [Diagram 2] 1 is a block diagram illustrating an embodiment of an optical pulse source. [Diagram 3] 1 is a block diagram illustrating an embodiment of an optical pulse source. [Figure 4] 1 is a block diagram illustrating an embodiment of an optical pulse source. [Diagram 5] FIG. 1 is a block diagram illustrating an embodiment of an optical pulse source. [Figure 6] 1 is a block diagram illustrating an embodiment of an optical pulse source. [Figure 7] 1 is a block diagram illustrating an embodiment of an optical pulse source. [Figure 8] FIG. 1 is a block diagram illustrating an embodiment of an optical pulse source. [Figure 9] FIG. 1 is a block diagram illustrating an embodiment of an optical pulse source. [Figure 10] 1 is a block diagram illustrating an embodiment of an optical pulse source and an embodiment of an optical system for Rydberg excitation. [Figure 11] 1 is a block diagram illustrating an embodiment of an optical pulse source and an embodiment of an optical system for Rydberg excitation. [Figure 12] 1 is a block diagram illustrating an embodiment of an optical pulse source and an embodiment of an optical system for Rydberg excitation. [Figure 13] 1 is a block diagram illustrating an embodiment of an optical pulse source and an embodiment of an optical system for Rydberg excitation. [Figure 14] 1 is a flow chart illustrating one embodiment of a method for forming a light pulse. [Figure 15] FIG. 1 shows an optical system for Rydberg excitation. [Figure 16] 1 illustrates a method for generating a laser light pulse. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The same reference numbers are used for corresponding features in the different embodiments. Referring to FIG. 1, one embodiment provides an optical pulse source 100 comprising a first laser 110, a second laser 112, an optical modulation device 120, an optical amplification device 130, and an optical frequency conversion device 140.

[0038] The first laser 110 is configured to output laser light at a first wavelength. The second laser 112 is configured to output laser light at a second wavelength different from the first wavelength. The optical modulation device 120 is configured to apply amplitude modulation to a first laser light of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse. The optical amplification device 130 is configured to amplify the first laser light pulse and the second laser light of the laser light at the first wavelength or the laser light at the second wavelength. The optical frequency conversion device 140 is configured to perform optical frequency conversion using the first laser light pulse and the second laser light of the laser light at the first wavelength or the laser light at the second wavelength to form an output laser light pulse at a third wavelength. The third wavelength is shorter than the first wavelength and the second wavelength.

[0039] One embodiment provides an optical pulse source 200 as shown in Figure 2. In this embodiment, the optical modulation device comprises a first optical modulator 220, e.g., an acousto-optic modulator (AOM) configured to apply amplitude modulation to a laser light at a first wavelength. The optical amplification device comprises a first optical amplifier 230 configured to amplify the first laser light pulses and a second optical amplifier 232 configured to amplify the laser light at a second laser light of the laser light at the first wavelength or the laser light at a second wavelength.

[0040] In one embodiment, the first optical amplifier 230 is configured to be continuously pumped. The first optical amplifier may be, for example, one of an Erbium-doped fiber amplifier (EDFA), an Ytterbium-doped fiber amplifier (YDFA), a Thulium-doped fiber amplifier (TDFA), or a Holmium-doped fiber amplifier (HDFA). The choice of which of these types of optical amplifiers depends on the first wavelength of the laser light generated by the first laser 110, as is well known to those skilled in the art.

[0041] One embodiment provides an optical pulse source 300 as shown in FIG. 3. In this embodiment, the optical modulation device comprises a first optical modulator 220 and a second optical modulator 320. For example, the first and second optical modulators 220, 320 can be AOMs. The first optical modulator 220 is configured to apply amplitude modulation to the laser light at a first wavelength to form a first laser light pulse at the first wavelength. The second optical modulator 320 is configured to apply amplitude modulation to the laser light at a second wavelength to form a second laser light pulse at the second wavelength.

[0042] The optical amplification apparatus comprises a first optical amplifier 230 configured to amplify a first laser light pulse and a second optical amplifier 232 configured to amplify a second laser light pulse.

[0043] In one embodiment, the first optical amplifier 230 is configured to be continuously pumped and the second optical amplifier 232 is configured to be continuously pumped. Each of the optical amplifiers may be, for example, one of an Erbium-doped fiber amplifier (EDFA), an Ytterbium-doped fiber amplifier (YDFA), a Thulium-doped fiber amplifier (TDFA), or a Holmium-doped fiber amplifier (HDFA). The choice of which of these types of optical amplifiers depends on the wavelength of the laser light generated by each of the first laser and the second laser, as is well known to those skilled in the art.

[0044] One embodiment provides an optical pulse source 350 as shown in Figure 4, where the optical modulation device is further configured to apply phase modulation to one of the laser light at the first wavelength or the laser light at the second wavelength. In the embodiment illustrated in Figure 4, the optical modulation device comprises a first IQ modulator 352 and a second IQ modulator 354. The first IQ modulator is configured to apply amplitude modulation and phase modulation to the laser light at the first wavelength to form a first laser light pulse at the first wavelength. The second IQ modulator is configured to apply amplitude modulation and phase modulation to the laser light at the second wavelength to form a second laser light pulse at the second wavelength.

[0045] The optical modulation device of this embodiment may alternatively comprise a first AOM, a first electro-optical modulator (EOM), a second AOM, and a second EOM. The first AOM is configured to apply amplitude modulation to a laser light at a first wavelength to form a first laser light pulse at the first wavelength, and the first EOM is configured to apply phase modulation to the first laser light pulse. The second AOM is configured to apply amplitude modulation to a laser light at a second wavelength to form a second laser light pulse at the second wavelength, and the second EOM is configured to apply phase modulation to the second laser light pulse.

[0046] 5 and 6, one embodiment provides an optical pulse source 400 further comprising a photodetector 402 and an output pulse control apparatus comprising a controller 404. The optical pulse source 400 may be any suitable optical pulse source. The photodetector is configured to detect the pulse shape of the laser light pulses output from the optical frequency converter 140 and generate an output signal indicative of the detected pulse shape. The controller comprises an interface circuit 406, a processor 408, and a memory 410. The memory comprises instructions 412 executable by the processor such that the controller operates as follows: The controller operates to receive an output signal indicative of the detected pulse shape from the photodetector.

[0047] The controller is operative to determine a difference between the detected pulse shape and a target pulse shape. The controller is operative to determine a compensating pulse shape for the first pulse of laser light. The compensating pulse shape is configured to at least partially compensate for the difference between the detected pulse shape and the target pulse shape. Thus, the compensating pulse shape compensates for pulse shape disturbances introduced by the optical amplification device and / or the optical frequency conversion device.

[0048] For example, if the target pulse shape is a square pulse as shown in FIG. 6(a) and the detected pulse shape is approximately square with an initial peak (i.e., with a pulse shape disturbance) as shown in FIG. 6(b), a compensating pulse generally having the pulse shape shown in FIG. 6(c) can be used to compensate for the difference, thereby producing a square output pulse in which the pulse disturbance is at least partially compensated.

[0049] The controller operates to generate at least one drive signal for an optical modulation device, in this example, a drive signal for the first optical modulator 220. The drive signal is configured to cause the first optical modulator to apply amplitude modulation to form a first laser light pulse having a compensating pulse shape.

[0050] Alternatively, in the embodiment of the optical pulse source 420 shown in FIG. 7, the optical detector is configured to detect the pulse shape of the laser light pulses output from the optical amplification device, e.g., the laser light pulses output from the first optical amplifier 230.

[0051] In one embodiment, the at least one drive signal is further configured to cause the optical modulator to apply amplitude modulation to form first laser light pulses having a pulse duration of up to 1 μs and a pulse repetition rate within the range of 0.1 kHz to 1 MHz.

[0052] In one embodiment, the first laser light pulse has a pulse duration of up to 500 ns. In one embodiment, the first laser light pulse has a pulse duration in the range 1 ns to 500 ns. In one embodiment, the controller operates to generate drive signals for the first optical modulator 220 and the second optical modulator 320 to cause the optical modulators to modulate the laser light at the first wavelength and the laser light at the second wavelength, respectively, to form the first laser light pulse and the second laser light pulse, which are square pulses with a pulse duration of 150 ns and a pulse repetition rate of 1 kHz. Using the same drive signal advantageously means that the first laser light pulse and the second laser light pulse are synchronized.

[0053] The first optical amplifier is configured to be continuously pumped to amplify the first laser light pulse to an average power of at least 3 mW, and the second optical amplifier is configured to be continuously pumped to amplify the second laser light pulse to an average power of at least 3 mW. By pumping the optical amplifier to amplify the average power of at least 3 mW, the first laser light pulse and the second laser light pulse will be amplified to a pulse peak power of 20 W, since 20 W x 150 ns x 1 kHz = 3 mW. Thus, the first laser light pulse and the second laser light pulse output from each optical amplifier are square pulses with a peak power of 20 W, a pulse duration of 150 ns, and a pulse repetition rate of 1 kHz, but the optical amplifiers are only required to be continuously pumped to amplify to a relatively low average power of 3 mW.

[0054] In one embodiment, the controller 404 is operative to determine a first compensatory pulse shape for the first laser light pulse and a second compensatory pulse shape for the second laser light pulse. The controller is operative to generate a first drive signal for the first optical modulator 220 and a second drive signal for the second optical modulator 320. The first drive signal is configured to cause the first optical modulator to apply amplitude modulation to form the first laser light pulse having the first compensatory pulse shape. The second drive signal is configured to cause the second optical modulator to apply amplitude modulation to form the second laser light pulse having the second compensatory pulse shape.

[0055] In one embodiment, the target pulse shape is one of a rectangular pulse or a Gaussian pulse. In one embodiment, the controller 404 is further operative to determine a phase offset for the first laser light pulse. The controller is additionally operative to generate at least one drive signal configured to cause the optical modulation device to additionally apply phase modulation to the one of the laser light at the first wavelength or the laser light at the second wavelength to form the first laser light pulse with a phase offset between subsequent laser light pulses.

[0056] 8 illustrates an optical pulse source 450 according to an embodiment in which the first optical modulator is further configured to apply phase modulation to the laser light at the first wavelength and the second optical modulator is further configured to apply phase modulation to the laser light at the second wavelength. For example, the first optical modulator is a first IQ modulator 352 and the second optical modulator is a second IQ modulator 354.

[0057] The controller 454 of this embodiment is further operative to determine a phase offset for the first and second laser light pulses. The controller is operative to generate at least one drive signal configured to cause the first optical modulator to additionally apply a phase modulation to the laser light at the first wavelength to form a first laser light pulse with a phase offset between subsequent first laser light pulses and the second optical modulator to additionally apply a phase modulation to the laser light at the second wavelength to form a second laser light pulse with a phase offset between subsequent second laser light pulses.

[0058] Alternatively, the optical detector may be configured to detect the pulse shape of the laser light pulses output from the optical amplification device, for example the laser light pulses output from the first optical amplifier 230.

[0059] 9 illustrates an optical pulse source 500 according to an embodiment in which the optical modulation device 540 comprises a sum frequency generation (SFG) device 542 and a second harmonic generation (SHG) device 544. The SFG device 542 is configured to perform sum frequency generation using the first laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a sum frequency laser light pulse. The SHG device 544 is configured to perform frequency doubling of the sum frequency laser light pulse to form an output laser light pulse.

[0060] In one embodiment, the first laser 510 is configured to output laser light at a first wavelength within a first wavelength range of 1050 nm to 1110 nm or 1535 nm to 1590 nm. The second laser 512 is configured to output laser light at a second wavelength within a second wavelength range of 1050 nm to 1110 nm or 1535 nm to 1590 nm. The output laser light pulses have a wavelength of one of 317 nm or 318 nm.

[0061] In one embodiment, the first laser 510 is configured to output laser light at a first wavelength value of 1064 nm or 1560 nm. The second laser 512 is configured to output laser light at a second wavelength value of 1064 nm or 1560 nm. The output laser light pulses have a wavelength of 317 nm.

[0062] In one embodiment, the first laser 510 is configured to output laser light at a first wavelength value of 1072.8 nm or 1550 nm. The second laser 512 is configured to output laser light at a second wavelength value of 1072.8 nm or 1550 nm. The output laser light pulses have a wavelength of 317 nm.

[0063] In one embodiment, the first laser 510 is configured to output laser light at a first wavelength value of 1078.6 nm or 1550 nm. The second laser 512 is configured to output laser light at a second wavelength value of 1078.6 nm or 1550 nm. The output laser light pulses have a wavelength of 318 nm.

[0064] 10 illustrates an optical pulse source 600 according to an embodiment in which the optical frequency conversion device 640 comprises a first SHG device 642, an SFG device 644, and a second SHG device 646. The first SHG device 642 is configured to frequency double the first laser light pulse to form a frequency doubled laser light pulse. The SFG device 644 is configured to perform sum frequency generation using the frequency doubled laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a sum frequency laser light pulse. The second SHG device 646 is configured to frequency double the sum frequency laser light pulse to form an output laser light pulse.

[0065] In one embodiment, the first laser 610 is configured to output laser light at a first wavelength value of 1566 nm or 1966 nm. The second laser 612 is configured to output laser light at a second wavelength value of 1566 nm or 1966 nm. The output laser light pulses have a wavelength of 302 nm.

[0066] In one embodiment, the first laser 610 is configured to output laser light at a first wavelength value of 1559 nm or 1970 nm. The second laser 612 is configured to output laser light at a second wavelength value of 1559 nm or 1970 nm. The output laser light pulses have a wavelength of 302 nm.

[0067] 11 illustrates an optical pulse source 700 according to an embodiment in which the optical frequency conversion device 740 comprises a first SHG device 742, a DFG device 744, and a second SHG device 746. The first SHG device 742 is configured to frequency double the first laser light pulse to form a frequency doubled laser light pulse. The DFG device 744 is configured to perform difference frequency generation using the frequency doubled laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a difference frequency laser light pulse. The second SHG device 746 is configured to frequency double the difference frequency laser light pulse to form an output laser light pulse.

[0068] In one embodiment, the first laser 710 is configured to output laser light at a first wavelength value of 1560 nm or 1092 nm. The second laser 712 is configured to output laser light at a second wavelength value of 1560 nm or 1092 nm. The output laser light pulses have a wavelength of 420 nm.

[0069] 12, one embodiment provides an optical system 750 for Rydberg excitation. The optical system 750 comprises an optical pulse source 100 as described above and an excitation chamber 752.

[0070] 13, one embodiment provides an optical system 800 for Rydberg excitation. The optical system 800 comprises an optical pulse source 850 and an excitation chamber 802.

[0071] The optical pulse source 850 comprises a first laser 810 , a second laser 812 , optical modulation devices 220 , 320 , optical amplification devices 230 , 232 , and an optical frequency conversion device 540 . The first laser 810 is configured to output laser light at a first wavelength. The second laser 812 is configured to output laser light at a second wavelength, different from the first wavelength.

[0072] The optical modulation device comprises a first optical modulator 220 and a second optical modulator 320. The first optical modulator 220 is configured to apply amplitude modulation to a laser light at a first wavelength to form a first laser light pulse at the first wavelength. The second optical modulator 320 is configured to apply amplitude modulation to a laser light at a second wavelength to form a second laser light pulse at the second wavelength.

[0073] The optical amplification apparatus comprises a first optical amplifier 230 configured to amplify a first laser light pulse and a second optical amplifier 232 configured to amplify a second laser light pulse.

[0074] The optical frequency conversion device 540 is configured to perform optical frequency conversion using the first laser light pulse and the second laser light pulse to form an output laser light pulse at a third wavelength. The third wavelength is shorter than the first wavelength and the second wavelength. The optical frequency conversion device 540 includes a sum frequency generation (SFG) device 542 and a second harmonic generation (SHG) device 544. The SFG device 542 is configured to perform sum frequency generation using the first laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a sum frequency laser light pulse. The SHG device 544 is configured to perform frequency doubling of the sum frequency laser light pulse to form an output laser light pulse.

[0075] In one embodiment, the first laser 810 is configured to output laser light at a first wavelength within a first wavelength range of 1050 nm to 1110 nm or 1535 nm to 1590 nm. The second laser 812 is configured to output laser light at a second wavelength within a second wavelength range of 1050 nm to 1110 nm or 1535 nm to 1590 nm. The output laser light pulses have a wavelength of one of 317 nm or 318 nm.

[0076] In one embodiment, the first laser 810 is configured to output laser light at a first wavelength value of 1064 nm or 1560 nm. The second laser 812 is configured to output laser light at a second wavelength value of 1064 nm or 1560 nm. The output laser light pulses have a wavelength of 317 nm. Thus, the optical system 800 of this embodiment can be used for Rydberg excitation of strontium (Sr) atoms.

[0077] In one embodiment, the first laser 810 is configured to output laser light at a first wavelength value of 1072.8 nm or 1550 nm. The second laser 812 is configured to output laser light at a second wavelength value of 1072.8 nm or 1550 nm. The output laser light pulses have a wavelength of 317 nm. Thus, the optical system 800 of this embodiment can be used for Rydberg excitation of strontium (Sr) atoms.

[0078] In one embodiment, the first laser 810 is configured to output laser light at a first wavelength value of 1078.6 nm or 1550 nm. The second laser 812 is configured to output laser light at a second wavelength value of 1078.6 nm or 1550 nm. The output laser light pulses have a wavelength of 318 nm. Thus, the optical system 800 of this embodiment can be used for Rydberg excitation of cesium (Cs) atoms.

[0079] 14, one embodiment provides an optical system 900 for Rydberg excitation. The optical system 900 comprises an optical pulse source 950 and an excitation chamber 902.

[0080] The optical pulse source 950 comprises a first laser 910 , a second laser 912 , optical modulation devices 220 , 320 , optical amplification devices 230 , 232 , and an optical frequency conversion device 640 . The optical modulation device and the optical amplification device are as described above with reference to FIG.

[0081] The optical frequency conversion device 640 is configured to perform optical frequency conversion using the first and second laser light pulses to form output laser light pulses at a third wavelength. The third wavelength is shorter than the first and second wavelengths. The optical frequency conversion device 640 includes a first SHG device 642, an SFG device 644, and a second SHG device 646. The first SHG device 642 is configured to perform frequency doubling of the first laser light pulses to form frequency doubled laser light pulses. The SFG device 644 is configured to perform sum frequency generation using the frequency doubled laser light pulses and the other of the laser light at the first wavelength or the laser light at the second wavelength to form sum frequency laser light pulses. The second SHG device 646 is configured to perform frequency doubling of the sum frequency laser light pulses to form output laser light pulses.

[0082] In one embodiment, the first laser 910 is configured to output laser light at a first wavelength value of 1566 nm or 1966 nm. The second laser 912 is configured to output laser light at a second wavelength value of 1566 nm or 1966 nm. The output laser light pulses have a wavelength of 302 nm. Thus, the optical system 900 of this embodiment can be used for Rydberg excitation of ytterbium (Yb) atoms.

[0083] In one embodiment, the first laser 910 is configured to output laser light at a first wavelength value of 1559 nm or 1970 nm. The second laser 912 is configured to output laser light at a second wavelength value of 1559 nm or 1970 nm. The output laser light pulses have a wavelength of 302 nm. Thus, the optical system 900 of this embodiment can be used for Rydberg excitation of ytterbium (Yb) atoms.

[0084] 15, one embodiment provides an optical system 1000 for Rydberg excitation. The optical system 1000 comprises an optical pulse source 1050 and an excitation chamber 1002.

[0085] The optical pulse source 1050 comprises a first laser 1010 , a second laser 1012 , optical modulation devices 220 , 320 , optical amplification devices 230 , 232 , and an optical frequency conversion device 640 .

[0086] The optical modulation device and the optical amplification device are as described above with reference to FIG. The optical frequency conversion device 740 is configured to perform optical frequency conversion using the first and second laser light pulses to form output laser light pulses at a third wavelength. The third wavelength is shorter than the first and second wavelengths. The optical frequency conversion device 740 includes a first SHG device 742, a DFG device 744, and a second SHG device 746. The first SHG device 742 is configured to perform frequency doubling of the first laser light pulses to form frequency doubled laser light pulses. The DFG device 744 is configured to perform difference frequency generation using the frequency doubled laser light pulses and the other of the laser light at the first wavelength or the laser light at the second wavelength to form difference frequency laser light pulses. The second SHG device 746 is configured to perform frequency doubling of the difference frequency laser light pulses to form output laser light pulses.

[0087] In one embodiment, the first laser 1010 is configured to output laser light at a first wavelength value of 1560 nm or 1092 nm. The second laser 1012 is configured to output laser light at a second wavelength value of 1560 nm or 1092 nm. The output laser light pulses have a wavelength of 420 nm. Thus, the optical system 1000 of this embodiment can be used for Rydberg excitation of rubidium (Rb) atoms.

[0088] Referring to FIG. 16, an embodiment provides a method 1100 of generating laser light pulses. The method includes generating 1102 laser light at a first wavelength and generating 1104 laser light at a second wavelength different from the first wavelength. Then, the method includes applying amplitude modulation to a first one of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse 1106. The method further includes amplifying 1108 the first laser light pulse and the second one of the laser light at the first wavelength or the laser light at the second wavelength. Then, the method includes performing optical frequency conversion using the first laser light pulse and the second one of the laser light at the first wavelength or the laser light at the second wavelength to form an output laser light pulse at a third wavelength shorter than the first wavelength and the second wavelength 1110.

[0089] item [Item 1] a first laser (110, 510, 610, 710, 810, 910, 1010) configured to output laser light at a first wavelength; a second laser (112, 512, 612, 712, 812, 912, 1012) configured to output laser light at a second wavelength different from the first wavelength; an optical modulation device (120, 220, 320, 352, 354) configured to apply amplitude modulation to a first one of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse; an optical amplifier (130, 230, 232) configured to amplify the first laser light pulse and a second one of the laser light at the first wavelength or the laser light at the second wavelength; an optical frequency conversion device (140, 540, 640, 740) configured to perform optical frequency conversion using the first laser light pulse and the second one of the laser light at the first wavelength or the laser light at the second wavelength to form an output laser light pulse at a third wavelength that is shorter than the first wavelength and the second wavelength; A light pulse source (100, 200, 300, 350, 400, 450, 850, 950, 1050).

[0090] [Item 2] 2. The optical pulse source of claim 1, wherein the optical modulation device comprises a first optical modulator (220, 352) configured to apply amplitude modulation to one of the laser light at the first wavelength or the laser light at the second wavelength to form the first laser light pulse.

[0091] [Item 3] 3. The optical pulse source of claim 2, wherein the optical modulation device further comprises a second optical modulator (320, 354), the first optical modulator (220, 352) configured to apply amplitude modulation to the laser light at the first wavelength to form first laser light pulses at the first wavelength, and the second optical modulator configured to apply amplitude modulation to the laser light at the second wavelength to form second laser light pulses at the second wavelength.

[0092] [Item 4] 4. The optical pulse source of claim 3, wherein the optical amplification device comprises a first optical amplifier (230) configured to amplify the first laser light pulse and a second optical amplifier (232) configured to amplify the second laser light pulse.

[0093] [Item 5] 5. The optical pulse source of any one of claims 1 to 4, wherein the optical amplifier device is configured to be continuously pumped.

[0094] [Item 6] a photodetector (402) configured to detect a pulse shape of a laser light pulse and to generate an output signal indicative of the detected pulse shape; The output pulse control device further comprises an interface circuit (406), at least one processor (408), and a controller (404, 454) comprising a memory (410) comprising instructions (412, 452) executable by the processor, the controller comprising: - receiving an output signal from the photodetector indicative of a detected pulse shape; - determining a difference between the detected pulse shape and a target pulse shape; - determining a compensating pulse shape for the first pulse of laser light, the compensating pulse shape being configured to at least partially compensate for the difference; - generating at least one drive signal for the optical modulation device, the at least one drive signal configured to cause the optical modulation device to apply amplitude modulation to form first laser light pulses having the compensation pulse shape; 6. An optical pulse source according to any one of items 1 to 5, which operates as follows:

[0095] [Item 7] 7. The optical pulse source of claim 6 when dependent on claim 3, wherein the controller (404, 454) is operative to determine at least one of a first compensation pulse shape for the first laser light pulse or a second compensation pulse shape for the second laser light pulse, and the at least one drive signal is configured to cause at least one of the first optical modulator to apply amplitude modulation to form the first laser light pulse having the first compensation pulse shape or the second optical modulator to apply amplitude modulation to form the second laser light pulse having the second compensation pulse shape.

[0096] [Item 8] 8. The optical pulse source of claim 6 or 7, wherein the target pulse shape is one of a rectangular pulse or a Gaussian pulse.

[0097] [Item 9] 9. The optical pulse source of any one of items 6 to 8, wherein the at least one drive signal is further configured to cause the optical modulation device to apply amplitude modulation to form first laser light pulses having a pulse duration of up to 1 μs, such as up to 500 ns, such as in the range 1 ns to 500 ns, and a pulse repetition rate in the range 0.1 kHz to 1 MHz.

[0098] [Item 10] 10. The optical pulse source of claim 1, wherein the optical modulation device (120, 352, 354) is further configured to apply a phase modulation to the one of the laser light at the first wavelength or the laser light at the second wavelength, and the controller (454) is further operative to generate the at least one drive signal configured to determine a phase offset for the first laser light pulse and to cause the optical modulation device to additionally apply phase modulation to the one of the laser light at the first wavelength or the laser light at the second wavelength to form the first laser light pulse with the phase offset between subsequent laser light pulses.

[0099] [Item 11] Item 11. The optical pulse source of item 10 when dependent on item 3, wherein the first optical modulator (352) is further configured to apply a phase modulation to the laser light at the first wavelength, and the second optical modulator (354) is further configured to apply a phase modulation to the laser light at the second wavelength, and the controller (454) is further operative to generate the at least one drive signal configured to determine a phase offset for the first laser light pulse and the second laser light pulse, and to cause the first optical modulator to additionally apply a phase modulation to the laser light at the first wavelength to form the first laser light pulse with the phase offset between subsequent first laser light pulses, and to cause the second optical modulator to additionally apply a phase modulation to the laser light at the second wavelength to form the second laser light pulse with the phase offset between subsequent second laser light pulses.

[0100] [Item 12] 12. An optical pulse source according to any one of claims 1 to 11, wherein the optical frequency conversion device (140, 540, 640, 740) is configured to perform the optical frequency conversion by one of second harmonic generation (SHG) and sum frequency generation (SFG) or difference frequency generation (DFG).

[0101] [Item 13] The optical frequency conversion device (140, 540) an SFG device (542) configured to perform sum frequency generation using the first laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a sum frequency laser light pulse; a second harmonic generation (SHG) device (544) configured to frequency double the sum frequency laser light pulses to form the output laser light pulses; Item 13. The optical pulse source of item 12, comprising:

[0102] [Item 14] Item 14. The optical pulse source of item 13, wherein the first wavelength is within a first wavelength range of the range 1050 nm to 1110 nm or the range 1535 nm to 1590 nm, the second wavelength is within a second wavelength range of the range 1050 nm to 1110 nm or the range 1535 nm to 1590 nm, and the output laser light pulses have a wavelength of one of 317 nm or 318 nm.

[0103] [Item 15] Item 15. The optical pulse source of item 14, wherein the first wavelength is a first wavelength value of 1064 nm or 1560 nm, the second wavelength is a second wavelength value of 1064 nm or 1560 nm, and the output laser light pulses have a wavelength of 317 nm.

[0104] [Item 16] Item 15. The optical pulse source of item 14, wherein the first wavelength is a first wavelength value of 1072.8 nm or 1550 nm, the second wavelength is a second wavelength value of 1072.8 nm or 1550 nm, and the output laser light pulses have a wavelength of 317 nm.

[0105] [Item 17] Item 15. The optical pulse source of item 14, wherein the first wavelength is a first wavelength value of 1078.6 nm or 1550 nm, the second wavelength is a second wavelength value of 1078.6 nm or 1550 nm, and the output laser light pulses have a wavelength of 318 nm.

[0106] [Item 18] The optical frequency conversion device (140, 640) a first SHG device (642) configured to frequency double the first laser light pulse to form a frequency doubled laser light pulse; an SFG device (644) configured to perform sum frequency generation using the frequency doubled laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a sum frequency laser light pulse; a second SHG device (646) configured to frequency double the sum frequency laser light pulse to form the output laser light pulse; Item 13. The optical pulse source of item 12, comprising:

[0107] [Item 19] Item 19. The optical pulse source of item 18, wherein the first wavelength is a first wavelength value of 1566 nm or 1966 nm, the second wavelength is a second wavelength value of 1566 nm or 1966 nm, and the output laser light pulses have a wavelength of 302 nm.

[0108] [Item 20] Item 19. The optical pulse source of item 18, wherein the first wavelength is a first wavelength value of 1559 nm or 1970 nm, the second wavelength is a second wavelength value of 1559 nm or 1970 nm, and the output laser light pulses have a wavelength of 302 nm.

[0109] [Item 21] The optical frequency conversion device (140, 740) a first SHG device (742) configured to frequency double the first laser light pulse to form a frequency doubled laser light pulse; a DFG device (744) configured to perform difference frequency generation using the frequency doubled laser light pulse and the other of the laser light at the first wavelength or the laser light at the second wavelength to form a difference frequency laser light pulse; a second SHG device (746) configured to frequency double the difference frequency laser light pulse to form the output laser light pulse; Item 13. The optical pulse source of item 12, comprising:

[0110] [Item 22] 22. The optical pulse source of claim 21, wherein the first wavelength is a first wavelength value of 1560 nm or 1092 nm, the second wavelength is a second wavelength value of 1560 nm or 1092 nm, and the output laser light pulses have a wavelength of 420 nm.

[0111] [Item 23] 23. An optical system (750, 800, 900, 1000) for Rydberg excitation comprising an optical pulse source (100, 200, 300, 350, 400, 450, 500, 600, 700, 850, 950, 1050) as described in any one of items 1 to 22 and an excitation chamber (752, 802, 902, 1002).

[0112] [Item 24] 1. A method (1100) for generating laser light pulses, comprising: Producing laser light at a first wavelength (1102); Producing (1104) laser light at a second wavelength different from the first wavelength; applying amplitude modulation to a first one of the laser light at the first wavelength or the laser light at the second wavelength to form a first laser light pulse (1106); amplifying (1108) the first laser light pulse and a second one of the laser light at the first wavelength or the laser light at the second wavelength; performing optical frequency conversion using the first laser light pulse and the second one of the laser light at the first wavelength or the laser light at the second wavelength to form an output laser light pulse at a third wavelength that is shorter than the first wavelength and the second wavelength (1110); A method (1100) comprising:

Claims

1. a first laser (110, 510, 610, 710, 810, 910, 1010) configured to output laser light at a first wavelength; a second laser (112, 512, 612, 712, 812, 912, 1012) configured to output laser light at a second wavelength different from the first wavelength; an optical modulation device (120, 220, 320, 352, 354) configured to apply amplitude modulation to a first laser light, the first laser light being one of the laser light at the first wavelength and the laser light at the second wavelength, to form a first laser light pulse; an optical amplifier (130, 230, 232) configured to amplify the first laser light pulse and a second laser light, the second laser light being one of the laser light at the first wavelength and the laser light at the second wavelength; an optical frequency conversion device (140, 540, 640, 740) configured to perform optical frequency conversion using the first laser light pulse and the second laser light, the second laser light being one of the laser light at the first wavelength and the laser light at the second wavelength, to form an output laser light pulse at a third wavelength that is shorter than the first wavelength and the second wavelength; 1. An optical pulse source (100, 200, 300, 350, 400, 450, 850, 950, 1050) comprising:

2. 2. The optical pulse source of claim 1, wherein the optical modulation device comprises a first optical modulator (220, 352) configured to apply amplitude modulation to one of the laser light at the first wavelength and the laser light at the second wavelength to form the first laser light pulse.

3. 3. The optical pulse source of claim 2, wherein the optical modulation device further comprises a second optical modulator (320, 354), the first optical modulator (220, 352) configured to apply amplitude modulation to the laser light at the first wavelength to form first laser light pulses at the first wavelength, and the second optical modulator configured to apply amplitude modulation to the laser light at the second wavelength to form second laser light pulses at the second wavelength.

4. 4. The optical pulse source of claim 3, wherein the optical amplification device comprises a first optical amplifier (230) configured to amplify the first laser light pulse and a second optical amplifier (232) configured to amplify the second laser light pulse.

5. 5. An optical pulse source as claimed in any one of claims 1 to 4, wherein the optical amplifying device is adapted to be continuously pumped.

6. a photodetector (402) configured to detect a pulse shape of a laser light pulse and to generate an output signal indicative of said detected pulse shape; and an output pulse control device comprising an interface circuit (406), at least one processor (408), and a controller (404, 454) comprising a memory (410) containing instructions (412, 452) executable by said processor, said controller comprising: receiving an output signal from said photodetector indicative of the detected pulse shape; determining a difference between the detected pulse shape and a target pulse shape; - determining a compensating pulse shape for said first pulse of laser light, said compensating pulse shape being configured to at least partially compensate for said difference; generating at least one drive signal for said optical modulation device, the drive signal being configured to cause said optical modulation device to apply amplitude modulation to form first laser light pulses having said compensation pulse shape; 6. An optical pulse source according to claim 1 , which operates as follows:

7. 7. The optical pulse source of claim 6, which relies on claim 3, wherein the controller (404, 454) is operative to determine at least one of a first compensation pulse shape for the first laser light pulse and a second compensation pulse shape for the second laser light pulse, and the at least one drive signal is configured to at least one of: cause the first optical modulator to apply amplitude modulation to form the first laser light pulse having the first compensation pulse shape; and cause the second optical modulator to apply amplitude modulation to form the second laser light pulse having the second compensation pulse shape.

8. 8. An optical pulse source as claimed in claim 6 or claim 7, wherein the target pulse shape is one of a rectangular pulse and a Gaussian pulse.

9. 9. An optical pulse source according to claim 6, wherein the at least one drive signal is further configured to cause the optical modulator device to apply amplitude modulation to form first laser light pulses having a pulse duration of up to 1 μs, such as up to 500 ns, for example in the range 1 ns to 500 ns, and a pulse repetition rate in the range 0.1 kHz to 1 MHz.

10. the optical modulation device (120, 352, 354) is further configured to apply a phase modulation to the one of the laser light at the first wavelength and the laser light at the second wavelength; The controller (454) determining a phase offset for the first pulse of laser light; generating the at least one drive signal configured to cause the optical modulation device to additionally apply a phase modulation to the one of the laser light at the first wavelength and the laser light at the second wavelength to form the first laser light pulse with the phase offset between subsequent laser light pulses; 10. An optical pulse source according to claim 1 further operable to:

11. the first optical modulator (352) is further configured to apply a phase modulation to the laser light at the first wavelength, and the second optical modulator (354) is further configured to apply a phase modulation to the laser light at the second wavelength; The controller (454) determining a phase offset for the first pulse of laser light and the second pulse of laser light; generating the at least one drive signal configured to cause the first optical modulator to additionally apply a phase modulation to the laser light at the first wavelength to form the first laser light pulse with the phase offset between subsequent first laser light pulses and the second optical modulator to additionally apply a phase modulation to the laser light at the second wavelength to form the second laser light pulse with the phase offset between subsequent second laser light pulses; 11. The optical pulse source of claim 10, which recites claim 3, further operable to:

12. 12. An optical pulse source according to any one of claims 1 to 11, wherein the optical frequency conversion device (140, 540, 640, 740) is configured to perform the optical frequency conversion by second harmonic generation (SHG) and one of sum frequency generation (SFG) and difference frequency generation (DFG).

13. The optical frequency conversion device (140, 540) an SFG device (542) configured to perform sum frequency generation using the first laser light pulse and the other of the laser light at the first wavelength and the laser light at the second wavelength to form a sum frequency laser light pulse; a SHG device (544) configured to frequency double the sum-frequency laser light pulses to form the output laser light pulses; 13. The optical pulse source of claim 12, comprising:

14. The optical frequency conversion device (140, 640) a first SHG device (642) configured to frequency double the first laser light pulse to form a frequency doubled laser light pulse; an SFG device (644) configured to perform sum frequency generation using the frequency doubled laser light pulse and the other of the laser light at the first wavelength and the laser light at the second wavelength to form a sum frequency laser light pulse; a second SHG device (646) configured to frequency double the sum-frequency laser light pulse to form the output laser light pulse; 13. The optical pulse source of claim 12, comprising:

15. The optical frequency conversion device (140, 740) a first SHG device (742) configured to frequency double the first laser light pulse to form a frequency doubled laser light pulse; a DFG device (744) configured to perform difference frequency generation using the frequency doubled laser light pulse and the other of the laser light at the first wavelength and the laser light at the second wavelength to form a difference frequency laser light pulse; a second SHG device (746) configured to frequency double the difference frequency laser light pulse to form the output laser light pulse; 13. The optical pulse source of claim 12, comprising:

16. An optical system (750, 800, 900, 1000) for Rydberg excitation, comprising an optical pulse source (100, 200, 300, 350, 400, 450, 500, 600, 700, 850, 950, 1050) according to any one of claims 1 to 15 and an excitation chamber (752, 802, 902, 1002).

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