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Picosecond Pulsed Sources

LDH Series

Picosecond Laser Diode Heads for PDL 800-D / PDL 828

  • Wavelengths between 375 and 1990 nm
  • Pulse widths as short as 40 ps (FWHM)
  • Adjustable (average) power up to 50 mW
  • Repetition rate from single shot to 80 MHz
  • Optional dual mode: pulsed and CW operation
  • Collimating optics, optional fiber coupling and peltier cooling

The LDH Series laser heads are ideally suited for any application that requires picosecond pulses with variable repetition rates. Since we use a wide variety of laser diode types for our LDH laser heads, we can offer a broad range of wavelengths, power values, and spectral widths. Each laser head includes control electronics specially matched to the diode and collimating optics. Different types of optical fibers can also be fitted to laser output.

Pulse widths below 100 ps

All LDH laser heads can generate pulses with a temporal width of ca. 100 ps (FWHM), while some models can achieve pulse widths of less than 40 ps. Temporal pulse width depends on the power level at which the laser head is operated (i.e. pulse width broadens with increasing power).

Adjustable average power of several mW

Example of pulse profiles of the LDH-P-C-485B at different output powersLaser heads of the LDH Series are designed to produce nearly constant pulse energy at a given intensity setting. The commonly achieved pulse energies are typically around a few tens of pJ. At repetition rates of 40 or 80 MHz, this corresponds to average output powers of several mW. Note that with increased output power, the diodes temporal pulse profile will always broaden and might show addition peaks or shoulders.

By varying the total number of carriers (i.e., the driving current) in the diode it is possible to change the output power of the diode. However, a higher pulse power, i.e., a higher injected current leads to additional oscillations inside the laser diode. These oscillations can be seen as Example of pulse profiles of the LDH-P-C-640B at different output powersadditional peaks or shoulders in the temporal pulse profile. As a consequence, an increased output power of the diode always results in an increased pulse width and a non-uniform temporal pulse shape. "Clean" and near symmetrical pulses can only be achieved close to the lasing threshold.

Repetition rates up to 80 MHz

When operated in conjunction with a laser driver from the PDL Series, all heads from the LDH Series are capable of repetition rates ranging from 1 Hz to several tens of MHz. Depending on diode used, maximum rates of 40 MHz for blue laser heads (with wavelengths shorter than 530 nm) and  80 MHz for red emitting ones can be achieved.

Pulsed and cw operation

LDH-D laser heads can be operated in either pulsed or cw mode. When run in cw mode, they can reach optical output powers up to 200 mW, while power in pulsed mode is identical to that of an LDH-P laser head with the same emission wavelength. Note that dual operation mode is only available when using a PDL 800-D or PDL 828 “Sepia II” laser driver.


General specifications

Beam parameters
Optics focus length

f' = 4.5 mm (Typ. for LDH-P/D-C-xxx)

f' = 9.0 mm (Typ. for LDH-D-TA-xxx)

Numerical aperture 0.55
Typical divergence (with optics)

Theta parallel 0.11 mrad

Theta perpendicular 0.32 mrad

Polarization typ. linear, perpendicular to the longer axis of the elliptical beam*
PER typ. > 1:10 (> 10 dB)
Side mode suppression ratio (SMSR) typ. < 0.01
Cooling
Peltier cooling stability better than 1 K for ambient temperature between 15°C and 30°C
Dimensions
Cooled 62 × 100 mm (diameter × length)
Cooled with fiber coupling 62 × 132 mm (diameter × length)
Uncooled 25 × 76 mm (diameter × length)
Uncooled with fiber coupling 25 × 106 mm (diameter × length)
"F-type" with FC/APC connector 195 × 112 × 24 mm (l × w × h)
Spectral width**
Wavelengths < 900 nm approx. 2 to 8 nm
Wavelengths > 900 nm approx. 10 to 20 nm
CW operation < 1 nm
Power stability (cooled)
12 hours, Delta T (ambient) < 3 K 1 % RMS, 3 % peak to peak

* a few exceptions to this behavior might occur  ** narrower bandwidth might be available on request

 

Laser Class Sign

Pulse-to-pulse jitter

LDH Series - Pulse to pulse jitterThe image on the right shows a typical measurement result of the pulse-to-pulse jitter. In this case the measurement result is 2.6 ps.


The following tables list wavelengths, pulse parameters, and power values of all available LDH laser heads. Low and high power settings in each line refer to the same head. Shortest pulses will be achieved with the “low” settings, while “high” settings will result in highest pulse power at moderate pulse length. Dual mode operation (pulsed / cw) is only available when operating an LDH-D laser head with a PDL 800-D or PDL 828 “Sepia II”. Note that each laser head has a spectral width of a few nm. Head with narrower spectral spread might be available upon request.


All Information given here is reliable to our best knowledge. However, no responsibility is assumed for possible inaccuracies or omissions. Specifications and external appearances are subject to change without notice.

The following table lists the pulse parameters and power values of the available wavelengths of the LDH Series (available between 266 and 530 nm with max. repetition rate of 40 MHz and between 530 and 2000 nm with max. repetition rate of 80 MHz). The two power adjustment levels specified here refer to the same laser head. These levels can be adjusted using the corresponding driver of the PDL Series. The 'Low' adjustment is the best choice for shortest pulses and is usually reached close to the lasing threshold. The 'High' adjustment is used to achieve highest pulse power at moderate pulse length and corresponds to the maximum intensity setting of the driver. Dual mode laser head (LDH-D Series, pulsed and CW operation) can only be controlled by the PDL 800-D or PDL 828 "Sepia II" laser driver. These laser heads have a spectral width of a few nm. Special selected laser heads with narrow spectral bandwidth can also be provided.

The table below is regularly updated based on data from recently manufactured laser heads. Other specifications such
as shorter pulse widths or higher powers might be possible depening on the performance of diodes in stock.
Please contact us for more information.

Wavelength
(± 10) [nm]
Type
(LDH-)
Pulse*
(FWHM) [ps]
Max rep rate
[MHz]
High avg. power**
[mW]
Low avg. power***
[mW]
CW power
[mW]
266 (± 3) P-FA-266 Please see separate data sheet for LDH-P-FA Series
355 (± 3) P-FA-355 Please see separate data sheet for LDH-P-FA Series
375 P-C-375 < 40 40 2.0 0.8 --
  P-C-375B < 40 40 4.0 1.0 --
  D-C-375 < 40 40 4.0 1.0 10
  P-C-375M < 90 40 10.0 2.5 --
  D-C-375M < 90 40 10.0 2.5 50
395 P-C-390 < 70 40 5.0 1.0 --
  D-C-390 < 70 40 5.0 1.0 30
405 P-C-405 < 50 80 4.0 0.8 --
  P-C-405B < 50 40 3.0 1.0 --
  D-C-405 < 50 40 3.0 1.0 50
  P-C-405M < 90 40 25.0 10.0 --
420 P-C-420 < 70 40 5.0 0.5 --
  D-C-420 < 70 40 5.0 0.5 30
440 P-C-440 < 80 40 2.0 0.4 --
  P-C-440B < 80 40 4.0 0.8 --
  D-C-440 < 80 40 4.0 0.8 50
  P-C-440M < 100 40 25.0 10.0 --
  D-C-440M < 100 40 25.0 10.0 200
450 P-C-450 < 100 40 2.0 0.5 --
  P-C-450B < 70 40 5.0 0.7 --
  D-C-450 < 70 40 5.0 0.7 10
455 P-C-450M < 90 40 20.0 4.0 --
  D-C-450M < 90 40 20.0 4.0 200
470 P-C-470 < 70 40 4.0 0.8 --
  P-C-470B < 170 40 5.0 1.3 --
  D-C-470 < 70 40 4.0 0.8 60
  P-C-470M < 120 40 20.0 8.0 --
  D-C-470M < 120 40 20.0 8.0 200
485 P-C-485 < 110 40 2.0 0.4 --
  P-C-485B < 90 40 5.0 0.7 --
  D-C-485**** < 90 40 5.0 0.7 50
500 P-C-500 < 130 40 2.0 0.5 --
  P-C-500B < 100 40 5.0 0.7 --
  D-C-500 < 100 40 5.0 0.7 40
510 P-C-510 < 130 40 2.0 0.3 --
  P-C-510B < 110 40 4.0 0.6 --
  D-C-510**** < 110 40 4.0 0.6 40
515 (± 3) P-FA-515L Please see separate data sheet for LDH-P-FA Series
520 P-C-520 < 130 40 2.5 0.7 --
  D-C-520**** < 130 40 2.5 0.7 20
  P-C-520M < 160 40 25.0 6.0 --
532 (± 3) P-FA-530B/L/XL Please see separate data sheet for LDH-P-FA Series
  D-TA-530 < 70 80 0.7 0.3 10
  D-TA-530B < 70 80 1.1 0.5 20
557 (± 3) P-FA-560 Please see separate data sheet for LDH-P-FA Series
561 (± 3) D-TA-560 < 80 80 0.5 0.3 5
  D-TA-560B < 70 80 0.7 0.5 20
594 (± 3) D-TA-595 < 80 80 0.3 0.2 5
  D-TA-595B < 80 80 0.5 0.4 5
635 P-635 < 90 80 4.0 0.6 --
  P-C-635M < 120 80 20.0 4.0 --
  D-C-635M < 120 80 20.0 4.0 100
640 P-C-640B < 90 80 20.0 2.0 --
  D-C-640 < 90 80 20.0 2.0 50
655 P-650 < 70 80 6.0 0.9 --
  P-C-650 < 90 80 6.0 0.9 --
  D-C-650 < 90 80 6.0 0.9 10
660 P-660 < 90 80 10.0 1.0 --
  P-C-660 < 90 80 10.0 1.0 --
  D-C-660 < 90 80 10.0 1.0 30
665 P-670B < 90 80 4.0 0.7 --
  P-C-670B < 90 80 4.0 0.7 --
  D-C-670B < 90 80 4.0 0.7 15
670 P-670 < 70 80 2.0 0.7 --
  P-C-670 < 70 80 2.0 0.7 --
  D-C-670 < 70 80 2.0 0.7 3
  P-C-670M < 120 40 50.0 9.0 --
685 P-690 < 70 80 8.0 1.0 --
  P-C-690 < 70 80 8.0 1.0 --
  D-C-690 < 70 80 8.0 1.0 20
705 P-705 < 70 80 10.0 2.0 --
  P-C-705 < 70 80 10.0 2.0 --
  D-C-705 < 70 80 10.0 2.0 20
730 P-730 < 100 80 4.0 1.5 --
  P-C-730 < 70 80 6.0 2.0 --
  D-C-730 < 70 80 6.0 2.0 15
760 P-760 < 100 80 6.0 0.9 --
  P-C-760 < 90 80 7.0 0.6 --
  D-C-760 < 90 80 7.0 0.6 15
766 (± 3) P-FA-765XL Please see separate data sheet for LDH-P-FA Series
785 P-780 < 70 80 10.0 1.0 --
  P-C-780 < 70 80 10.0 1.0 --
  D-C-780 < 70 80 10.0 1.0 40
805 P-810 < 90 80 10.0 0.9 --
  P-C-810 < 90 80 10.0 0.9 --
  D-C-810 < 90 80 10.0 0.9 30
805 P-C-810M < 90 80 30.0 3.0 --
  D-C-810M < 90 80 30.0 3.0 100
830 P-830 < 70 80 8.0 0.3 --
  P-C-830 < 70 80 8.0 0.3 --
  D-C-830 < 70 80 8.0 0.3 20
830 P-C-830M < 90 80 30.0 10.0 --
  D-C-830M < 90 80 30.0 10.0 100
840 P-840 < 80 80 4.0 0.5 --
  P-C-840 < 80 80 4.0 0.5 --
  D-C-840 < 80 80 4.0 0.5 30
850 P-850 < 70 80 9.0 1.0 --
  P-C-850 < 70 80 9.0 1.0 --
  D-C-850 < 70 80 9.0 1.0 40
905 P-905 < 120 80 5.0 1.0 --
  P-C-905 < 120 80 8.0 2.0 --
  D-C-905 < 120 80 8.0 2.0 50
930 P-930 On request
  P-C-930 On request
  D-C-930 On request
950 P-950 On request
  P-C-950 On request
  D-C-950 On request
965 P-965 < 90 80 20.0 2.5 --
975 P-980 On request
  P-C-980 On request
  D-C-980 On request
976 P-F-980 < 110 80 25.0 7.0  
  D-F-980 < 110 80 25.0 7.0 200
1025 P-F-1030 < 90 80 10.0 2.0 --
1060 (± 20) P-1060 < 90 80 20.0 1.5 --
  P-C-1060 < 90 80 20.0 1.5 --
  D-C-1060 < 90 80 20.0 1.5 50
1063 (± 3) P-FA-1060/XL Please see separate data sheet for LDH-P-FA Series
1080 P-C-1080 < 50 80 4.0 2.5 --
  D-C-1080 < 50 80 4.0 2.5 30
1120 P-C-1120 < 90 80 5.0 2.5 --
  D-C-1120 < 90 80 5.0 2.5 20
1310 (± 20) P-1310 < 50 80 2.0 0.15 --
  P-C-1310 < 50 80 2.0 0.15 --
  D-C-1310 < 50 80 2.0 0.15 5
1532 (± 3) P-FA-1530/XL Please see separate data sheet for LDH-P-FA Series
1550 (± 30) P-1550 < 50 80 1.0 0.02 --
  P-C-1550 < 50 80 1.0 0.02 --
  D-C-1550 < 50 80 1.0 0.02 2.5
1990 (± 40) P-F-1990 < 120 80 0.3 0.1 --

* Shortest pulse width at min intensity setting above laser threshold. Possible pulse broadening at high intensity settings.
 Pulses are deconvoluted with 30 ps detection IRF. Shorter pulse widths are available on demand.
** Average optical power at max repetition rate and max intensity setting.
*** Average optical power at max repetition rate and min intensity setting above laser threshold.
**** Different coupling efficiency into optical fibers for pulsed and CW operation due to astigmatism.

Naming scheme of the LDH Series laser heads

LDH naming scheme

Description:

"C": Laser head with thermoelectric cooler, mandatory for some laser heads, optional for all other laser heads.

"F": Laser head emits a divergent beam from FC/APC fiber output connector

"M": Transversal multi mode structure, reduced coupling efficiency into single mode fibers

On request: narrow spectral bandwidth

The given specification are for information only, possible changes may occur.

Wavelength      
Central
[nm]
Variation
[nm]
Type****
(LDH-)
Linewidth
(FWHM) [nm]
Pulse*
(FWHM) [ps]
Max Rep Rate
[mHz]
Low avg power**
[mW]
High avg power**
[mW]
760 ±3 P-C-N-760 < 0.2 < 90 80 0.9 6.0
782 ±3 P-C-N-780     On request    
852 ±3 P-C-N-850 < 0.3 < 100 80 1.5 9.0
976 ±3 P-C-N-976 < 0.5 < 90 80 10.0 10.0
1063 ±3 P-F-N-1064 < 0.5 < 100 80 0.9 10.0
1064 ±3 P-C-N-1064 < 1 < 130 80 1.3 10.0
1275 ±7 P-C-N-1310 < 0.5 < 40 80 0.03 1.3
1300 ±7 P-C-N-1310 < 0.5 < 40 80 0.03 1.3
1310 ±7 P-C-N-1310 < 0.5 < 40 80 0.03 1.3
1325 ±7 P-C-N-1310 < 0.5 < 40 80 0.03 1.3
1349 ±7 P-C-N-1310 < 0.5 < 40 80 0.03 1.3
1417 ±3 P-C-N-1415 < 0.2 < 100 80 0.03 1.0
1470 ±3 P-C-N-1550 <0.2 < 40 80 0.05 1.3
1490 ±3 P-C-N-1550 < 0.2 < 40 80 0.05 1.3
1510 ±3 P-C-N-1550 < 0.2 < 40 80 0.05 1.3
1530 ±3 P-C-N-1550 < 0.2 < 40 80 0.05 1.3
1550 ±3 P-C-N-1550 < 0.2 < 40 80 0.05 1.3
1570 ±3 P-C-N-1550 < 0.2 < 40 80 0.05 1.3
1590 ±3 P-C-N-1550 < 0.2 < 40 80 0.05 1.3
1610 ±3 P-C-N-1550 < 0.2 < 40 80 0.05 1.3
Available upon request: 760, 763, 780, 795, 937, 1083 nm (± 3 nm)

* Shortest pulse width at min intensity setting above laser threshold. Possible pulse broadening at high intensity settings. The instrument response function of 30 ps is deconvoluted. Shorter pulse widths are available on demand.
** Average optical power at max repetition rate and max intensity setting.
*** Average optical power at max repetition rate and min intensity setting above laser threshold.
**** LDH-D-C-N types including CW mode are available as well.
 

Laser Class Sign

Other wavelength as well as wavelength selection are available upon special request. All measurements shown may be subject to a 10% callibration error.

Each laser head undergoes an extensive burn-in test to ensure long-term stability and is shipped with a comprehensive set of test data. This test data is kept in our database, which already holds records of more than 15 years.

All Information given here is reliable to our best knowledge. However, no responsibility is assumed for possible inaccuracies or omissions. Specifications and external appearances are subject to change without notice.


The standard output of every laser head of the LDH Series is a collimated beam. However, all laser heads of the LDH Series can also be coupled to optical fibers: multi mode, single mode or polarisation maintaining single mode with different connector types. For the majority of applications an angled FC/APC connector at the laser head is recommended to prevent backreflections into the fiber that could interfere with the laser stability. The output connector of the fiber is preferably an angled FC/APC, while alternative connectors such as FC/PC or SMA are also possible. Coupling of the laser into an optical fiber has the benefit that the elliptical beam shape is transformed into a round beam at the output of the fiber. For a single mode fiber, the resulting beam is even nicely gaussian shaped. However, fiber coupling also leads to a reduced output at the end of the fiber. Typical coupling efficiencies are around 40% for a single mode fiber and around 80% for a multi mode fiber. A collimator at the fiber output can also be provided upon request.

Possible fiber types Typical coupling efficiency
Single mode fiber > 40 %
Polarisation maintining single mode fiber > 40 %
Multi mode fiber > 80 %

Connector types

  • FC/APC connectors are recommended for the majority of applications. The end of this fiber is cut by 8°, which minimizes backreflections into the fiber that might interfere with the laser stability. This connector is therefore always used at the laser head and preferably as well at the output of the fiber.
  • FC/PC connectors have a flat output end. They might be necessary at the output of the fiber, if it needs to be connected to a device that also has a FC/PC connector. In such cases one should take care that the optical path of a possible back reflected pulse does not match the selelcted pulse period.
  • SMA connectors are only suited for multi mode fibers due to their limited fixation accuracy. They have a flat output end.

Beam shape

Due to diffraction, the beam diverges rapidly after leaving the laser chip, typically at 30 degrees at the vertical (fast) axis by 10 degrees at the horizontal (slow) axis. This leads to an elliptical beam shape after the collimating optics with typical dimensions of 1.5 × 3.5 mm. The beam shape can be influenced using optical fibers.
 

Direct emission

LDH Series - Beam without fiber

All lasers emit a collimated beam with an elliptical beam shape with typical dimensions of 1.5 × 3.5 mm

Behind a multimode fiber

LDH Series - Beam after multi mode fiber

In case of a multi mode fiber, the beam shape after the fiber is nearly round. A speckle pattern emerges by interference of multiple modes inside the fiber.

Behind a single mode fiber

LDH Series - Beam after single mode fiber

In case of a single mode fiber, the beam shape after the fiber is a nice gaussian beam profile as only one mode is transmitted within the fiber



Latest 10 publications referencing Pulsed Diode Lasers (PDL Series, LDH-Series, LDH-FA Series)

The following list is an extract of 10 recent publications from our bibliography that either bear reference or are releated to this product in some way. Do you miss your publication? If yes, we will be happy to include it in our bibliography. Please send an e-mail to info@picoquant.com containing the appropriate citation. Thank you very much in advance for your kind co-operation.