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Picosecond Pulsed Sources

LDH Series

Picosecond Pulsed Diode Laser Heads

  • Wavelengths between 375 and 1990 nm
  • Pulse widths as short as 40 ps (FWHM)
  • Adjustable (average) power up to 20 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 laser heads of the LDH Series are the ideal product for all applications that require picosecond pulses at a variable repetition rate. They are build around a variety of different diode types, which allows to offer these heads at many wavelengths with different power values and spectral widths. Typically diode types like Fabry-Perot (FP), Distributed Feedback (DFB) or Distributed Bragg Reflector (DBR) are used. Each laser head contains additional special control electronics that are matched to the individual diode. The laser heads come with collimating optics and can be fitted with optical fibers (multi mode, single mode, or polarisation maintaining single mode).

Pulse widths below 100 ps

All laser heads emit picosecond pulses with a full width at half maximum (FWHM) around 100 ps or below at the "low power level", which is close to the lasing threshold. For some laser heads even pulse widths below 40 ps are possible. The pulse width itself cannot be controlled directly, but does depend on the selected power level (i.e., driving current) of the diode. At maximum driving current (“high power level”), the pulse width broadens due to shoulders or additional peaks.

Adjustable average power of several milliwatts

Example of pulse profiles of the LDH-P-C-485B at different output powersAll laser heads are designed to emit an about constant pulse energy at a given driving current. Doubling the repetition rate therefore effectively doubles the average output power. The achievable pulse energies are typically in the order of several tens of pico joule, which corresponds to maximum average output powers of several milliwatts at 40 MHz or 80 MHz repetition rate.

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

All laser heads are designed to work at repetition rates from single shot up to values in the MHz range. The maximum suggested repetition rate depends on each single diode and is typically 40 MHz for blue laser heads (wavelengths below 530 nm) and up to 80 MHz for red laser heads. Driving signals with repetition rates in the MHz range are readily delivered by the PDL Series drivers.

Pulsed and CW operation

As a special type, the laser heads of the LDH-D Series can be operated in pulsed and cw mode. In CW operation, they can emit up to 20 mW of output power, while in pulsed mode their performance is no different to the corresponding laser heads of the LDH-P Series. This dual mode operation is, however, only supported by the PDL 800-D and the PDL 828 “Sepia II” drivers.


General specifications

Beam parameters
Optics focus length f' = 4.5 mm
Numerical aperture 0.55
Typical divergence (with optics) Theta parallel 0.32 mrad
  Theta perpendicular 0.11 mrad
Polarisation typ. linear, perpendicular to the longer axis of the elliptical beam
Polarisation degree > 90 %
Side mode suppression ratio (SMSR) < 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

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.



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 updated on a regular basis based on data of recently manufactured laser heads. Other specifications such as shorter pulse widths or higher powers than listed below might be possible depening on the performance of diodes in stock. Please contact us for more information.

Laser heads between 266 and 530 nm (max. repetition rate 40 MHz)

  Power Adjust = Low (Narrow Pulse) Power Adjust = High (Wide Pulse)
Wavelength
( ± 10) [nm]
Type (LDH-) CW power
[mW]
Pulse FWHM
[ps]****
Average Power
(@ 40 MHz) [mW]
Pulse FWHM
[ps]
Average Power
(@ 40 MHz) [mW]
266 ( ± 3) P-FA-266 please see LDH-FA Series
355 ( ± 3) P-FA-355 please see LDH-FA Series
375 P-C-375 -- < 40 0.8 < 300 2.0
  P-C-375B -- < 40 1.0 < 300 4.0
  D-C-375 10 < 40 1.0 < 300 4.0
  P-C-375M -- < 90 2.5 < 300 10.0
  D-C-375M 50 < 90 2.5 < 300 10.0
395 P-C-390 -- < 70 1.0 < 300 5.0
  D-C-390 30 < 70 1.0 < 300 5.0
405 P-C-405 -- < 50 0.4 < 300 2.0
  P-C-405B -- < 50 1.0 < 500 3.0
  D-C-405 50 < 50 1.0 < 500 3.0
  P-C-405M -- < 90** 10.0 < 600 25.0
  D-C-405M 200 < 90** 10.0 < 600 25.0
420 P-C-420 -- < 70 0.5 < 300 5.0
  D-C-420 30 < 70 0.5 < 300 5.0
440 P-C-440 -- < 70 0.4 < 300 2.0
  P-C-440B -- < 70 0.8 < 500 4.0
  D-C-440 50 < 70 0.8 < 500 4.0
  P-C-440M -- < 100** 10.0 < 500 25.0
  D-C-440M 200 < 100** 10.0 < 500 25.0
450 P-C-450 -- < 100 0.5 < 300 2.0
  P-C-450B -- < 70 0.7 < 300 5.0
  D-C-450 10 < 70 0.7 < 300 5.0
455 P-C-450M -- < 90 4.0 < 300 20.0
  D-C-450M 200 < 90 4.0 < 300 20.0
470 P-C-470 -- < 70 0.4 < 500 2.0
  P-C-470B -- < 70 0.8 < 500 4.0
  D-C-470 40 < 70 0.8 < 500 4.0
  P-C-470M -- < 120 8.0 < 500 20.0
  D-C-470M 200 < 120 8.0 < 500 20.0
485 P-C-485 -- < 110 0.4 < 500 2.0
  P-C-485B -- < 90 0.7 < 550 5.0
  D-C-485* 50 < 90 0.7 < 550 5.0
500 P-C-500 -- < 130 0.5 < 500 2.0
  P-C-500B -- < 100 0.7 < 500 5.0
  D-C-500 40 < 100 0.7 < 500 5.0
510 P-C-510 -- < 130 0.3 < 600 2.0
  P-C-510B -- < 110 0.6 < 600 4.0
  D-C-510* 40 < 110 0.6 < 600 4.0
520 P-C-520 -- < 130 0.7 < 600 5.0
  D-C-520* 20 < 130 0.7 < 600 5.0
  P-C-520M -- < 160 8.0 < 300 25.0
532 ( ± 3) P-FA-530B/L/XL please see LDH-FA Series

Laser heads between 530 and 2000 nm (max. repetition rate 80 MHz)

  Power Adjust = Low (Narrow Pulse) Power Adjust = High (Wide Pulse)
Wavelength
( ± 10) [nm]
Type (LDH-) CW power
[mW]
Pulse FWHM
[ps]****
Average Power
(@ 80 MHz) [mW]
Pulse FWHM
[ps]
Average Power
(@ 80 MHz) [mW]
532 ( ± 3) D-TA-530 20 < 70 0.4 < 70 1.1
561 ( ± 3) D-TA-560 5 < 60 0.4 < 80 0.6
594 ( ± 3) D-TA-595 5 < 80 0.3 < 90 0.4
635 P-635 -- < 90 0.6 < 400 4.0
  P-C-635M -- < 120 4.0 < 500 20.0
  D-C-635M 100 < 120 4.0 < 500 20.0
640 P-C-640B -- < 90 2.0 < 500 20.0
  D-C-640 50 < 90 2.0 < 500 20.0
655 P-650 -- < 70 0.9 < 400 6.0
  P-C-650 -- < 90 0.9 < 400 6.0
  D-C-650 10 < 90 0.9 < 400 6.0
660 P-660 -- < 90 1.0 < 500 10.0
  P-C-660 -- < 90 1.0 < 500 10.0
  D-C-660 30 < 90 1.0 < 500 10.0
665 P-670B -- < 90 0.7 < 400 4.0
  P-C-670B -- < 90 0.7 < 400 4.0
  D-C-670B 15 < 90 0.7 < 400 4.0
670 P-670 -- < 70 0.7 < 300 2.0
  P-C-670 -- < 70 0.7 < 300 2.0
  D-C-670 3 < 70 0.7 < 300 2.0
  P-C-670M*** -- < 120 9.0 < 300 50.0
685 P-690 -- < 70 1.0 < 400 8.0
  P-C-690 -- < 70 1.0 < 500 8.0
  D-C-690 20 < 70 1.0 < 500 8.0
705 P-705 -- < 70 2.0 < 400 10.0
  P-C-705 -- < 70 2.0 < 400 10.0
  D-C-705 20 < 70 2.0 < 400 10.0
730 P-730 -- < 100 1.5 < 400 4.0
  P-C-730 -- < 70 2.0 < 400 6.0
  D-C-730 15 < 70 2.0 < 400 6.0
760 P-760 -- < 100 0.9 < 600 6.0
  P-C-760 -- < 90 0.9 < 600 6.0
  D-C-760 10 < 90 0.9 < 600 6.0
766 ( ± 3) P-FA-765 please see LDH-FA Series
785 P-780 -- < 70 1.0 < 500 10.0
  P-C-780 -- < 70 1.0 < 500 10.0
  D-C-780 40 < 70 1.0 < 500 10.0
805 P-810 -- < 90 0.9 < 500 10.0
  P-C-810 -- < 90 0.9 < 500 10.0
  D-C-810 30 < 90 0.9 < 500 10.0
  P-C-810M -- < 90 3.0 < 500 30.0
  D-C-810M 100 < 90 3.0 < 500 30.0
830 P-830 -- < 70 0.4 < 300 8.0
  P-C-830 -- < 70 0.4 < 300 8.0
  D-C-830 20 < 70 0.4 < 300 8.0
  P-C-830M -- < 90 10.0 < 300 30.0
  D-C-830M 100 < 90 10.0 < 300 30.0
840 P-840 -- < 80 0.5 < 500 4.0
  P-C-840 -- < 80 0.5 < 500 4.0
  D-C-840 30 < 80 0.5 < 500 4.0
850 P-850 -- < 70 1.0 < 500 9.0
  P-C-850 -- < 70 1.0 < 500 9.0
  D-C-850 40 < 70 1.0 <500 9.0
905 P-905 -- < 120 1.0 < 300 5.0
  P-C-905 -- < 120 2.0 < 300 8.0
  D-C-905 50 < 120 2.0 < 300 8.0
930 available upon request
950 available upon request
965 P-965 -- < 90 2.5 < 400 20.0
  P-C-965 -- < 90 2.5 < 400 20.0
  D-C-965 30 < 90 2.5 < 400 20.0
975 P-980

 

available upon request

  P-C-980
  D-C-980
976 P-F-980   < 110 3.5 < 500 12.0
  D-F-980 200 < 110 3.5 < 500 12.0
1025 P-F-1030 -- < 90 2.0 < 550 10.0
1060
(± 20)
P-1060 -- < 70 2.0 < 100 20.0
  P-C-1060 -- < 70 2.0 < 100 20.0
  D-C-1060 50 < 70 2.0 < 100 20.0
1063 ( ± 3) P-FA-1060/L Please see LDH-FA Series
1080 P-C-1080 -- < 50 2.5 < 50 4.0
  D-C-1080 30 < 50 2.5 < 50 4.0
1120 P-C-1120 -- < 90 2.5 < 90 5.0
  D-C-1120 20 < 90 2.5 < 90 5.0
1310
(± 20)
P-1310 -- < 50 0.15 < 500 2.0
  P-C-1310 -- < 50 0.15 < 500 2.0
  D-C-1310 5 < 50 0.15 < 500 2.0
1532 ( ± 3) P-FA-1530 Please see LDH-FA Series
1550
(± 30)
P-1550 -- < 50 0.02 < 400 1.0
  D-C-1550 2.5 < 50 0.02 < 400 1.0
1990 P-F-1990 -- < 120 0.1 < 500 0.3

*different coupling efficiency into optical fibers for pulsed and CW operation due to astigmatism
** shorter pulse width available on demand
*** maximal repetition rate 40 MHz
**** deconvoluted with instrument response function of 30ps

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

 

Narrow spectral bandwidth types (available upon request)

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

Wavelength   Power Adjust = Low (Narrow Pulse) Power Adjust = High (Wide Pulse)
Central
[nm]
Variation
[nm]
Spectral FWHM
[nm]
Pulse FWHM
[ps]
Average Power
(@ 80 MHz) [mW]
Pulse FWHM
[ps]
Average Power
(@ 80 MHz) [mW]
772 ±3 < 1 < 120 2.5 < 350 7.0
784 ±3 < 0.3 < 100 1.6 < 500 8.0
852 ±3 < 0.3 < 100 1.5 < 350 9.0
976 ±3 < 0.5 -- -- < 90 10.0
1063 ±3 < 0.5 < 100 0.9 < 700 10.0
1064 ±3 < 1 < 130 1.3 < 600 10.0
1275 ±7 < 0.5 < 40 0.03 < 250 1.3
1300 ±7 < 0.5 < 40 0.03 < 250 1.3
1310 ±7 < 0.5 < 40 0.03 < 250 1.3
1325 ±7 < 0.5 < 40 0.03 < 250 1.3
1349 ±7 < 0.5 < 40 0.03 < 250 1.3
1417 ±3 < 0.2 < 100 0.03 < 400 1.0
1470 ±3 <0.2 < 40 0.05 < 500 1.3
1490 ±3 < 0.2 < 40 0.05 < 500 1.3
1510 ±3 < 0.2 < 40 0.05 < 500 1.3
1530 ±3 < 0.2 < 40 0.05 < 500 1.3
1550 ±3 < 0.2 < 40 0.05 < 500 1.3
1570 ±3 < 0.2 < 40 0.05 < 500 1.3
1590 ±3 < 0.2 < 40 0.05 < 500 1.3
1610 ±3 < 0.2 < 40 0.05 < 500 1.3
1530 to 1560, any wavelength < 0.5 <100 0.4 < 900 5.0
Available upon request: 760, 763, 780, 795, 937, 1083 nm (± 3 nm)

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 fibre 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 fibre.
  • 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.