 |
|
Lambda
DG-4 / DG-5
Ultra High Speed Wavelength Switcher
|
|
|
|
|
|
| S
P E C S > L
A M B D A- D G - 4 |
Output
Range
330nm to 700nm - Ozone free
300nm to 700nm - Full spectrum |
Xenon
Lamp Type
175 Watt, pre-aligned, ozone free
(175W full spectrum available upon request) |
Lamp
Expected Lifetime
1,000 hours
(All bulbs warranted for 500 hours. Longer life depends on your application.) |
Power
Consumption
350 Watts |
Filter
Diameter
DG-4: Four, 25mm (1inch)
DG-5: Two, 25mm (1inch) and
Three 18mm |
Dimensions
10in x 10in x 19in
25cm x 25cm x 48cm |
Light
Guide
2 meters long
3mm diameter |
Weight
45lbs
20kg |
Electrical
115/230 Volts
50/60 Hertz power line |
|
|
|
|
The Lambda DG-4/DG-5 is a complete illumination system offering speed and versatility for experiments requiring rapid wavelength switching. The instrument retains
all the advantages of interference filter based systems, yet eliminates the temporal constraints imposed by traditional filter changing devices
like filter wheels. Switching between any two wavelengths is achieved in less than the 1.2msec vertical retrace period of a video
signal, allowing the user to perform real-time video imaging. The high switching speed of the Lambda DG-4/DG-5 facilitates
the ability to follow fast changes in ion concentrations in dual wavelength ratio imaging applications and to monitor other
concomitant changes in the studied system at additional wavelengths.
| F
E A T U R E S > LAMBDA DG-4 / DG-5 |
Complete
system for wavelength switching
The Lambda DG-4 / DG-5 is a complete integrated 175 (or 300) Watt light source
and wavelength switching excitation system.
Four or five interference filters can be easily installed in the
DG-4 or DG-5, respectively. An additional standard neutral density filter
can be inserted in the common path of the light.
The light guide output from the Lambda DG-4 / DG-5 provides uniform
spatial illumination, as well as vibration isolation from your microscope.
Cold mirror assembly eliminates IR radiation
Integral shuttering function
The Lambda DG-4 /DG-5 provides a high speed shutter function with
open/close times of 500µs. The shutter function reduces light intensity
by 5 to 6 orders of magnitude. A unique feature, turbo blanking, is available
to prevent transmission through intermediate filters when switching between non-adjacent
filter positions.
If complete light shuttering is required, a mechanical shutter (i.e. SmartShutter™)
can be incorporated into the Lambda DG-4 / DG-5.
Intensity attenuation function
The light intensity can be adjusted by offsetting the output galvanometer
such that light is not centered on the liquid light guide. Up to
15 logical filters can be defined with this method. Due to the scrambling
effect of the light pipe, the output still has excellent uniformity.
Direct insertion of neutral density optical filters is also possible
in any of the four filter holders. A final neutral density optical
filter can also be placed in the exiting light path which will reduce
the light output from all optical channels.
Two outputs for monitoring filter position
A 4 bit TTL signal transmits the current optical channel (filter)
position.
A digital-to-analog converter (DAC) output produces a voltage showing
which filter is in use.
Remote
interface
Computer control of the instrument is possible via parallel
or serial port.
|
Narrow bandpass systems, such as single cavity interference filters, grating
monochromators, and A.O. modulators, pass unwanted harmonics of the desired
wavelength. Also, with variable wavelength devices, it is not always possible to obtain
sufficient blocking of out-of-band wavelengths. Modern interference filters, as used
in the Lambda DG-4/DG-5, do not pass harmonics and have integral blocking
characteristics 1000 times better than typical monochromator systems. For the same full
width at half maximum (FWHM), interference filters have a narrower spectral bandpass
due to the absence of the slit function.
The dual galvanometer design of the Lambda DG-4/DG-5 allows tuning of the
relative intensities at each wavelength. This adjustment, in variable wavelength devices
with a single optical path, is difficult to obtain. Unlike monochromators and other wavelength
selective systems, the Lambda DG-4/DG-5 can be used as a source of white light when required.
How it works:
This unique optical design of the Lambda DG-4/DG-5 is based on dual scanning galvanometers utilizing interference filters
for wavelength selection. The light from the xenon arc lamp is focused on the first galvanometer mirror which directs it via a
parabolic mirror, through one of the interference filter channels. Following the filter, a second parabolic and a second
galvanometer mirror collect and redirect the light into the light guide. A cold mirror in the beginning of the light path eliminates
the IR radiation, reducing significantly the amount of heat absorbed by the optics and the sample. Cold mirrors modified to pass
near-IR to 780 to 880nm are also available.
A built-in shutter function allows reduction of light intesity by six orders of magnitude. For applications requiring mechanical shuttering,
like time lapse experiments or very sensitive samples, the SmartShutter™ can be integrated into the device to assure that
the light is completely blocked.
The standard system, the Lambda DG-4, holds up to four 25mm interference filters. The Lambda DG-5, a five filter version,
accommodates three 18mm and two 25mm filters. While the switching time between any two wavelengths is done in less than
1.2msec, the dwell time at any wavelength is arbitrarily set by the user.
The
light guide can be coupled to the illumination port of most microscopes using
an optional adapter.
|
