/ DG-5 Plus
Ultra High Speed Wavelength Switcher
P E C S >
LAMBDA - DG-4 / DG-5 PLUS
300 Watt pre-aligned, ozone free xenon arc bulb
(Full spectrum available upon request)
330nm to 700nm - Ozone free
300nm to 700nm - Full spectrum
Expected lifetime 1,000 hours
(All bulbs have a prorated warranty for 500 hours)
DG-4: Four, 25mm (1inch)
DG-5: Two, 25mm (1inch) and
10in x 10in x 19in
25cm x 25cm x 48cm
2 meters long
50/60 Hertz power line
The Lambda DG-4/DG-5 Plus 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 Plus 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.
E A T U R E S > LAMBDA DG-4 / DG-5 PLUS
COMPLETE SYSTEM FOR WAVELENGTH SWITCHING
The Lambda DG-4 / DG-5 Plus is a complete integrated 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 Plus, respectively. An additional standard
neutral density filter can be inserted in the common path of the
The light guide output from the Lambda DG-4 / DG-5 Plus provides uniform
spatial illumination, as well as vibration isolation from your microscope.
A cold mirror assembly eliminates IR radiation, extending the lifetime of the optics and the light guide and preventing the exposure of the sample to IR when white light is necessary.
The Lambda DG-4 /DG-5 Plus 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.
If complete light shuttering is required, a mechanical shutter (i.e. SmartShutter™)
can be incorporated into the Lambda DG-4 / DG-5 Plus.
INTEGRAL NEUTRAL DENSITY FILTERING
Neutral density filtering is achieved 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 guide, the output has excellent uniformity.
Direct insertion of neutral density optical filters is also possible
in the filter holders at any of the four optical channels. A final neutral density optical
filter can 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)
A digital-to-analog converter (DAC) output produces a voltage showing
which filter is in use.
The turbo blanking feature is designed for situations when the switching is done between non-adjacent filter positions. When the
instrument is in this mode, the input and output galvanometer mirrors move out of sync, thus preventing the sample from being exposed to light of unwanted wavelength
during switching and shuttering.
DIRECT COMPUTER CONTROL
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 Plus, 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 Plus 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 Plus can be used as a source of white light when
How it works:
This unique optical design of the Lambda DG-4/DG-5 Plus 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 Plus, holds up to four 25mm interference filters. The Lambda DG-5 Plus, 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 Lambda DG-4/DG-5 Plus provides 0.5msec switching times between adjacent filter positions and 20% greater light output.
light guide can be coupled to the illumination port of most microscopes using
an optional adapter.