Quantum Instruments Cascade Laser Starter Kit manual QCL pulser timing unit TPG128

Starter Kit Instruction Manual Description 24

4.7QCL pulser timing unit (TPG128)

4.7.1Description

The QCL pulser timing unit is designed to control the QCL pulser switching unit.

It provides TTL pulses on 50Ω on two indepen- dent outputs. The pulse duration is adjustable from 0 to 200ns. The interval between pulses can be ad- justed between 200ns and 105µs in 3 ranges.

A TTL level Gate in input and Trigger out output have also been included. The trigger pre- cedes the output pulse by about 100ns.

The QCL pulser timing unit includes the +12VDC power supply needed by the QCL pulser switching unit by means of a Lemo 00 connector with the +12V on the centre wire.

O

FF

T

P

1

G

O

2

w

N

8

−

T

er

TL

−−

Pu

−

−

−

0

se

G

+

−

−−

t

e

max

12

−

0.5 o

2.

ne

0

V

Perio

5

to

2∝

ra

60mA

V

to 1010.5 s

tor

d

−

5

∝s

0

−

−

∝s

to

2

G

50

−−

−

0

ns

ohm

at

s

−−

e I

−

N

Tri

50 oh

−

g

OU

ms

D r

T

ati

O

50 o

o

ut

hms

n

1

O

ut

2

Fig.10: QCL pulser timing unit

! Warning !

Although the pulser system is capable of delivering pulses with lengths up to 200 ns, and duty cycles up to 50%, the laser may not withstand this! The laser shall only be op- erated under conditions as specified in the datasheet or by Alpes Lasers directly: all other operation may result in destruction of the laser and loss of warranty.

4.7.2Specifications

Voltage : . . . . . . . . . . . . . . . . . . . . . . . . . 220V-240V

Frequency : . . . . . . . . . . . . . . . . . . . . . 50Hz-60Hz

Output voltage (for switching unit):+12VDC

Output max current (for switching unit):150mA

Delay between pulses:

. . . . . . . . . . . . . . . . . . . . . . . . 200 ns to 2.2 µs

. . . . . . . . . . . . . . . . . . . . . . 500 ns to 10.5 µs

. . . . . . . . . . . . . . . . . . . . . . .5.1µs to 105.1 µs

trigger and logic output signals: . . . 50Ω TTL driver circuit (74128)

gate level : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TTL

Maximum duty cycle: 50% (if larger cycles are needed, the LDD100 should be fed by an exter- nal 12V power supply, not the one provided in the TPG128, or else the fuse in the TPG128 may blow).

Limitations

Caution !

The generator can not operate with a 200 ns long pulse at a 200ns repetition interval, therefore it is limited in duty factor.

The following limitations apply:

T=400ns: . . . . . . . . . . . . . . . . . . . . t max = 200ns

T=300ns: . . . . . . . . . . . . . . . . . . . . t max = 200ns

T=250ns: . . . . . . . . . . . . . . . . . . . . t max = 150ns

T=200ns: . . . . . . . . . . . . . . . . . . . . t max = 100ns