1/8 m Monochromator

For general-purpose laboratory work or academic applications, the Oriel 77250 1/8 m Monochromator is a smart and economical choice. This simple, manually operated 1/8 m instrument has good resolution, low stray light and is very versatile. A large family of slits and gratings give a wide range of bandpasses and broad spectral coverage.

Optical Configuration

The optical configuration of the 77250 is the reason why throughput is so high while stray light performance is unrivaled. Fig. 1 shows the Ebert-Fastie design with two inline slits and an out of plane grating. Having the slits opposite each other lets you mount the complete optical system on a bench or rail. Having the grating out of plane eliminates re-entrant spectra.

Stray Light

The excellent stray light performance of the 77250 can be judged from the measurements below.

Measurement 1:

With a Deuterium Source, a UV-VIS PMT, and Holographic Grating blazed at 250 nm (model 77296 ), measurements were made with and without a glass plate in the beam. The stray radiation with the glass in place was 0.2% of the signal recorded at 210 nm without any glass, and 0.1% of the signal recorded at 250 nm. The signal at 210 nm with the glass in place was 0.1% of the signal at 210 nm without the glass. At 250 nm, the stray light signal was only 0.025% of the unblocked signal.

Measurement 2:

Using a HeNe laser at 632.8 nm focused on the slit in an F/4 cone, the average of the stray radiation readings at 612.8 and 652.8 nm was 0.008% of the signal at 632.8 nm. In this case, the response of the detector is irrelevant as the only light detected is at 632.8 nm.

Manual Wavelength Drive and Readout

The 77250 uses a hand crank to turn the grating. A 3-digit counter displays the wavelength directly in nanometers when using a 1200 l/mm grating. A calibrated wheel marked in 0.2 nm divisions lets you position and read the wavelength to 0.1 nm. For gratings with other line spacings, multiply the wavelength on the counter by the “Wavelength Counter Multiplier” listed in Table 1. The readout is factory set so the wavelength indicated is correct to within 1 nm through the full range of a 1200 l/mm grating. For greater accuracy, you can reset the readout within any restricted spectral region. The precision of this instrument is better than 0.2 nm, limited by backlash.

Interchangeable Gratings

Each grating is mounted in a protective frame. The frame has a tab for quick and easy insertion and removal without touching the surface of the grating. The following 30 x 30 mm replicated gratings are for the 77250 only; they cannot be used in any of our other Monochromators.

Table 1 Grating Specifications for 77250 1/8 m Monochromator

Three Types of Slits

We offer three types of slit assemblies for the 77250 in various slit sizes. Choose the same type and size for the input and output. Our slit assemblies have a 1.5 Inch Series male flange.

Micrometer Driven Slit Assembly

• Slit width is continuously variable from 4 µm to 3 mm
• Slit height is adjustable from 3 to 12 mm
• ±10 µm repeatability
• ±10 µm accuracy from 4 µm to 250 µm; ±5% from 250 µm to 3 mm

This assembly uses a micrometer drive to adjust the width from 4 µm to 3 mm.

Multiple Fixed Slit Assembly

• 8 fixed slit positions from 50 µm to 3.16 mm
• Slit height is adjustable from 1 to 12 mm

This assembly consists of a rotating disc with 8 fixed slits. A manual wheel rotates the disc, which has a positive detent for exact repeatability of slit position.

Fixed Slits

• Most economical for single slit size
• Fixed width and height

If you only need a few slit sizes, this is the most economical choice. These are precision slits fixed on a machined slide. You need the 77294 Fixed Slit Holder to hold the slit and mate it to the monochromator.

IR Long Pass Filters

Mounting

Rod mounting the 77250 allows the greatest flexibility; you can vary the optical axis height to match your source or detector. To rod mount the 77250 , order the 77387 Monochromator Mounting Plate and two Molded Composite Optical Mounting Posts.

Specifications

Monochromator and Accessories

To order a complete 77250 Monochromator, you must specify a grating and (2) slit assemblies separately.

	Model	Description	avail raw	Availability	price raw	Price	Qty.  MULTI ADD
	77250	1/8 m Monochromator; order grating and slit assemblies separately	6	6 Weeks	1999	$1,999.00	ADD
	74001	Micrometer Driven Variable Slit, 4 µm to 3 mm Width, 3 mm to 12 mm Height	0	In Stock	682	$682.00	ADD
	77269	Multiple Fixed Slit Wheel, 8 Slits, 50 µm to 3.16mm Width, 1-12 mm Height	5	5 Weeks	784	$784.00	ADD
	77294	Fixed Slit Holder	0	In Stock	197	$197.00	ADD
	77387	Monochromator Mounting Plate, 77250 Series	5	5 Weeks	176	$176.00	ADD

Gratings

	Model	Description	avail raw	Availability	price raw	Price	Qty.  MULTI ADD
	77296	Holographic Grating, 1200 l/mm, 250 nm Blaze, 77250 Series	99	Call	552	$552.00	ADD
	77298	Grating 1200 l/mm 350 nm RBLZ 1/8 m Ruled	0	In Stock	337	$337.00	ADD
	77299	Grating 600 l/mm 1 µm RBLZ 1/8 m Ruled	99	Call	341	$341.00	ADD
	77300	Grating 300 l/mm 2 µm RBLZ 1/8 m Ruled	99	Call	341	$341.00	ADD
	77301	Grating 150 l/mm 4 µm RBLZ 1/8 m Ruled	5	5 Weeks	341	$341.00	ADD
	77302	Grating 75 l/mm 7 µm RBLZ 1/8 m Ruled	5	5 Weeks	341	$341.00	ADD
	77303	Grating 50 l/mm 12 µm RBLZ 1/8 m Ruled	99	Call	341	$341.00	ADD
	77304	Grating 600 l/mm 200 nm RBLZ 1/8 m Ruled	6	6 Weeks	341	$341.00	ADD
	77305	Grating 600 l/mm 750 nm RBLZ 1/8 m Ruled	0	In Stock	341	$341.00	ADD
	77306	Grating 1200 l/mm 750 nm RBLZ 1/8 m Ruled	0	In Stock	341	$341.00	ADD
	77307	Grating 200 l/mm 1 µm RBLZ 1/8 m Ruled	99	Call	341	$341.00	ADD
	77308	Holographic Grating, 2400 l/mm, 250 nm Blaze, 77250 Series	99	Call	552	$552.00	ADD
	77309	Holographic Grating, 1800 l/mm, 500 nm Blaze, 77250 Series	6	6 Weeks	552	$552.00	ADD
	77310	Holographic Grating, 3600 l/mm, 405 nm Blaze, 77250 Series	5	5 Weeks	552	$552.00	ADD
	77316	Grating 600 l/mm 1.6 µm RBLZ 1/8 m Ruled	5	5 Weeks	341	$341.00	ADD
	77317	Grating 150 l/mm 800 nm RBLZ 1/8 m Ruled	5	5 Weeks	341	$341.00	ADD

Fixed Slits

	Model	Description	avail raw	Availability	price raw	Price	Qty.  MULTI ADD
	77219	Fixed Slit, 50 µm Width, 6 mm Height	0	In Stock	294	$294.00	ADD
	77218	Fixed Slit, 120 µm Width, 18 mm Height	0	In Stock	163	$163.00	ADD
	77217	Fixed Slit, 280 µm Width, 18 mm Height	0	In Stock	163	$163.00	ADD
	77216	Fixed Slit, 600 µm Width, 18 mm Height	0	In Stock	163	$163.00	ADD
	77215	Fixed Slit, 760 µm Width, 18 mm Height	0	In Stock	163	$163.00	ADD
	77214	Fixed Slit, 1240 µm Width, 18 mm Height	0	In Stock	163	$163.00	ADD
	77213	Fixed Slit, 1560 µm Width, 18 mm Height	0	In Stock	163	$163.00	ADD
	77212	Fixed Slit, 3160 µm Width, 18 mm Height	0	In Stock	163	$163.00	ADD
	77211	Fixed Slit, 6230 µm Width, 18 mm Height	6	6 Weeks	163	$163.00	ADD

IR Long Pass Filter

	Model	Description	avail raw	Availability	price raw	Price	Qty.  MULTI ADD
	57910	IR Long Pass Filter, 1.5 µm Cut-on, 1" Dia.	0	In Stock	702	$702.00	ADD
	57925	IR Long Pass Filter, 2.5 µm Cut-on, 1" Dia.	0	In Stock	702	$702.00	ADD
	57935	IR Long Pass Filter , 3.5 µm Cut-on, 1" Dia.	4	4 Weeks	890	$890.00	ADD
	57940	IR Long Pass Filter, 4.5 µm Cut-on, 1" Dia.	99	Call	1273	$1,273.00	ADD
	57955	IR Long Pass Filter, 7.5 µm Cut-on, 1" Dia.	99	Call	1428	$1,428.00	ADD

Newport Resource e-Catalogs *

• Newport Resource e-Catalog, pages 1280-1282 (English)
• Newport Resource e-Catalog, pages 1280-1282 (French)
• Newport Resource e-Catalog, pages 1280-1282 (German)