Molded Glass Aspheric Lenses: Finite Conjugate, Uncoated

High NA (0.10 to 0.52)
Diffraction-Limited Design
Focus Light with a Single Element
Finite Magnification for Focusing From a Point Source

C440TMD

(Not to Scale)

Application Idea

C440TMD Mounted Aspheric Lens in a Fiber Launch System

354450

355465

355915

Related Items

Other Aspheric Lenses

Air-Spaced Doublets

Aspheric Condensers with Diffusers

Laser Diodes

Spanner Wrenches

Aspheric Lens Kits

Flexure Stage Aspheric Lens Mounts

Fiber Launch

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Overview
Fiber Coupling
Lens Equation
Selection Guide
Feedback

Molded Glass Aspheric Lenses
Infinite Conjugate
Uncoated
350 - 700 nm (-A Coating)
600 - 1050 nm (-B Coating)
1050 - 1700 nm (-C Coating)
1.8 - 3 µm (-D Coating)
3 - 5 µm (-E Coating)
8 - 12 µm (-F Coating)
405 nm V-Coating
1064 nm V-Coating
Finite Conjugate
Uncoated

Webpage Features
	Click for complete specifications.
Performance Hyperlink	Click to view item-specific focal length shift data and spot diagrams at various wavelengths.

Zemax Files
Click on the red Document icon next to the item numbers below to access the Zemax file download. Our entire Zemax Catalog is also available.

Features

Molded Glass Aspheric Lenses Designed for Finite Magnification
Focus Light Without Introducing Spherical Aberration
All Lenses Available Unmounted
Available Pre-Mounted in a Nonmagnetic 303 Stainless Steel Lens Cell by Contacting Tech Sales

Aspheric lenses are designed to focus light without introducing spherical aberration into the transmitted wavefront. For monochromatic sources, spherical aberration is often what prevents a single spherical lens from achieving diffraction-limited performance when focusing light. Thus, an aspheric lens is often the best single element solution for many applications including coupling light into a fiber, spatial filtering, or imaging light onto a detector.

This page features our selection of uncoated, finite conjugate molded glass aspheric lenses. Please note that Thorlabs also offers a large selection of infinite molded aspheric lenses either uncoated or with one of our AR coatings deposited on both sides (see links in the Aspheric Lens Selection Guide table to the right).

The 355440 molded glass lens is available premounted in a nonmagnetic 303 stainless steel lens cell that is engraved with the mounted part number (Item # C440TMD) for easy identification. This mounted version has a metric thread that makes it easy to integrate into an optical setup or OEM application. Pre-mounted versions of our other aspheres are available as specials; for more information, please contact Tech Sales. Mounted aspheres are readily adapted to our SM1 series of lens tubes by using our Aspheric Lens Adapters. They can be used as a drop-in replacement for multi-element microscope objectives by combining the lens with our Microscope Objective Adapter Extension Tube.

Molded glass aspheres are manufactured from a variety of optical glasses to yield the indicated performance. The molding process will cause the properties of the glass (e.g., Abbe number) to deviate slightly from those given by glass manufacturers. Specific material properties for each lens can be found by clicking on the Info Icon () in the tables below and selecting the Glass tab.

Choosing a Lens

Aspheric lenses are commonly chosen to couple incident light with a diameter of 1 - 5 mm into a single mode fiber. A simple example will illustrate the key specifications to consider when trying to choose the correct lens.

Example:
Fiber: P1-630A-FC-2
Collimated Beam Diameter Prior to Lens: Ø3 mm

The specifications for the P1-630A-FC-2, 630 nm, FC/PC single mode patch cable indicate that the mode field diameter (MFD) is 4.3 μm. This specification should be matched to the diffraction-limited spot size given by the following equation:

$Equation for Diffraction-Limited Spot$

Here, f is the focal length of the lens, λ is the wavelength of the input light, and D is the diameter of collimated beam incident on the lens. Solving for the desired focal length of the collimating lens yields

focal length of collimating lens

Thorlabs offers a large selection of mounted and unmounted aspheric lenses to choose from. The aspheric lens with a focal length that is closest to 16 mm has a focal length of 15.29 mm (Item# 354260-B or A260-B). This lens also has a clear aperture that is larger than the collimated beam diameter. Therefore, this aspheric lens is the best option given the initial parameters (i.e., a P1-630A-FC-2 single mode fiber and a collimated beam diameter of 3 mm). Remember, for optimum coupling the spot size of the focused beam must be less than the MFD of the single mode fiber. As a result, if an aspheric lens is not available that provides an exact match, then choose the aspheric lens with a focal length that is shorter than the calculation above yields. Alternatively, if the clear aperture of the aspheric lens is large enough, the beam can be expanded before the aspheric lens, which has the result of reducing the spot size of the focus beam.

Click to Enlarge
Reference Drawing

Aspheric Lens Design Formula

Definitions of Variables
z	Sag (Surface Profile) as a Function of Y
Y	Radial Distance from Optical Axis
R	Radius of Curvature
k	Conic Constant
A_n	nth Order Aspheric Coefficient

The aspheric surfaces of these lenses may be described using a polynomial expansion in Y, the radial distance from the optical axis. The surface profile or sagitta (often abbreviated as sag) is denoted by z, and is given by the following expression:

where R is the radius of curvature, k is the conic constant, and the A_n are the nth order aspheric coefficients. The sign of R is determined by whether the center of curvature for the lens surface is located to the right or left of the lens' vertex; a positive R indicates that the center of curvature is located to the right of the vertex, while a negative R indicates that the center of curvature is located to the left of the vertex. For example, the radius of curvature for the left surface of a biconvex lens would be specified as positive, while the radius of curvature for its right surface would be specified as negative.

Aspheric Lens Coefficients

Due to the rotational symmetry of the lens surface, only even powers of Y are contained in the polynomial expansion above. The target values of the aspheric coefficients for each product can be found by clicking either on the blue Info Icons in the tables below ( info ) or on the red documents icon ( docs ) next to each lens sold below.

AR Coating Abbreviations
Abbreviation	Description
U	Uncoated: Optics Do Not have an AR Coating
A	Broadband AR Coating for the 350 - 700 nm Range
B	Broadband AR Coating for the 600 - 1050 nm or 650 - 1050 nm Range
C	Broadband AR Coating for the 1050 - 1620 nm or 1050 - 1700 nm Range
V	Narrowband AR Coating Designed for the Wavelength Listed in the Table Below

The table below contains all molded visible and near-IR aspheric lenses offered by Thorlabs. For our selection of IR molded aspheres, click here. The Item # listed is that of the unmounted, uncoated lens. An "X" in any of the five AR Coating Columns indicates the lens is available with that coating (note that the V coating availability is indicated with the AR coating wavelength). The table to the right defines each letter and lists the specified AR coating range. Clicking on the X takes you to the landing page where that lens (mounted or unmounted) can be purchased.

Base Item #	AR Coating Options					Effective Focal Length	NA	Outer Diameter of Unmounted Lens	Working Distance		Clear Aperture of Unmounted Lens
Base Item #	U	A	B	C	V	Effective Focal Length	NA	Outer Diameter of Unmounted Lens	Unmounted	Mounted	Clear Aperture of Unmounted Lens
355465	X					0.5 mm	S1: 0.50 S2: 0.10	1.845 mm	S1: 0.3 mm^a S2: 2.9 mm^a	-	S1: Ø0.40 mm S2: Ø0.70 mm
355915	X					0.8 mm	S1: 0.50 S2: 0.12	1.300 mm	S1: 0.7 mm^a S2: 3.9 mm^a	-	S1: Ø0.77 mm S2: Ø1.00 mm
355200	X					1.1 mm	S1: 0.43 S2: 0.12	2.400 mm	S1: 0.5 mm^b S2: 4.8 mm^a	-	S1: Ø1.24 mm S2: Ø1.24 mm
355201	X					1.1 mm	S1: 0.12 S2: 0.43	4.929 mm	S1: 0.5 mm^b S2: 4.8 mm^a	-	S1: Ø1.24 mm S2: Ø1.24 mm
354450	X					1.2 mm	S1: 0.30 S2: 0.30	1.800 mm	S1: 1.7 mm^a S2: 1.7 mm^a	-	S1: Ø1.14 mm S2: Ø1.14 mm
354710	X	X	X	X		1.5 mm	0.5	2.650 mm	0.5 mm^b	0.4 mm^b,c	S1: Ø1.15 mm S2: Ø1.50 mm
354140	X	X	X	X		1.5 mm	0.6	2.400 mm	0.8 mm^a	0.8 mm^a	S1: Ø1.14 mm S2: Ø1.60 mm
355755	X					1.9 mm	S1: 0.15 S2: 0.15	1.700 mm	S1: 3.6 mm^a S2: 3.6 mm^a	-	S1: Ø1.10 mm S2: Ø1.10 mm
355151	X	X	X	X		2.0 mm	0.5	3.000 mm	0.5 mm^b	0.3 mm^b,c	S1: Ø1.09 mm S2: Ø2.00 mm
355440	X	X	X	X		2.8 mm	S1: 0.3 S2: 0.5	4.700 mm	S1: 2.0 mm^bS2: 7.1 mm^a	S1: 1.8 mm^b,cS2: 7.09 mm^a	S1: Ø3.76 mm S2: Ø4.12 mm
355392	X	X	X	X		2.8 mm	0.6	4.000 mm	1.5 mm^a	1.0 mm^a,c	S1: Ø2.50 mm S2: Ø3.60 mm
355390	X	X	X	X		2.8 mm	0.6	4.500 mm	2.2 mm^a	2.0 mm^a,c	S1: Ø3.60 mm S2: Ø3.60 mm
355660	X	X	X	X		3.0 mm	0.5	4.000 mm	1.6 mm^a	1.3 mm^a,c	S1: Ø2.35 mm S2: Ø3.60 mm
354330	X	X	X	X		3.1 mm	0.7	6.325 mm	1.8 mm^a	1.8 mm^a,c	S1: Ø3.84 mm S2: Ø5.00 mm
N414		X	X	X		3.30 mm	0.47	4.50 mm	1.94 mm^a	1.83 mm^a,c	Ø3.52 mm
354340	X	X	X			4.0 mm	0.6	6.325 mm	1.48 mm^b	1.2 mm^b,c	S1: Ø3.77 mm S2: Ø5.10 mm
357610	X	X	X			4.0 mm	0.6	6.325 mm	1.5 mm^b	1.1 mm^b,c	S1: Ø3.39 mm S2: Ø4.80 mm
357775	X	X	X		405	4.0 mm	0.6	6.325 mm	1.9 mm^b	1.5 mm^b,c	S1: Ø3.45 mm S2: Ø4.80 mm
354350	X		X	X		4.5 mm	0.4	4.700 mm	2.2 mm^a	1.6 mm^a,c	S1: Ø2.05 mm S2: Ø3.70 mm
355230	X	X	X	X	1064	4.5 mm	0.6	6.325 mm	2.8 mm^b	2.4 mm^b,c	S1: Ø3.93 mm S2: Ø5.07 mm
A230	X	X	X	X		4.51 mm	0.55	6.34 mm	2.91 mm^a	2.53 mm^a,c	Ø4.95 mm
354453	X	X	X	X		4.6 mm	0.5	6.000 mm	2.0 mm^b	0.9 mm^b,c	S1: Ø3.38 mm S2: Ø4.80 mm
A390		X	X			4.60 mm	0.53	6.00 mm	2.70 mm^a	1.64 mm^a,c	Ø4.89 mm
354430	X		X	X		5.0 mm	0.2	2.000 mm	4.4 mm^a	4.0 mm^a,c	S1: Ø1.40 mm S2: Ø1.60 mm
354105	X	X	X	X		5.5 mm	0.6	7.200 mm	3.1 mm^b	2.0 mm^b,c	S1: Ø4.96 mm S2: Ø6.00 mm
354171	X	X	X	X		6.2 mm	0.3	4.700 mm	3.4 mm^b	2.8 mm^b,c	S1: Ø2.72 mm S2: Ø3.70 mm
355110	X	X	X	X	1064	6.2 mm	0.4	7.200 mm	2.7 mm^b	1.6 mm^b,c	S1: Ø2.93 mm S2: Ø5.00 mm
A110	X	X	X	X		6.24 mm	0.40	7.20 mm	3.39 mm^a	2.39 mm^a,c	Ø5.00 mm
A375		X	X	X		7.50 mm	0.30	6.51 mm	5.90 mm^a	5.59 mm^a,c	Ø4.50 mm
354240	X	X	X	X	1064	8.0 mm	0.5	9.950 mm	4.9 mm^b	3.8 mm^b,c	S1: Ø6.94 mm S2: Ø8.00 mm
A240	X	X	X	X		8.00 mm	0.50	9.94 mm	5.92 mm^a	4.79 mm^a,c	Ø8.00 mm
354060	X	X	X	X		9.6 mm	0.3	6.325 mm	7.5 mm^b	7.1 mm^b,c	S1: Ø5.13 mm S2: Ø5.20 mm
354061	X	X	X	X		11.0 mm	0.2	6.325 mm	8.9 mm^b	8.5 mm^b,c	S1: Ø4.63 mm S2: Ø5.20 mm
A220	X	X	X			11.00 mm	0.26	7.20 mm	7.97 mm^a	6.91 mm^a,c	Ø5.50 mm
354220	X	X	X	X	1064	11.0 mm	0.3	7.200 mm	6.9 mm^b	5.8 mm^b,c	S1: Ø4.07 mm S2: Ø5.50 mm
355397	X	X	X	X		11.0 mm	0.3	7.200 mm	9.3 mm^b	8.2 mm^b,c	S1: Ø6.24 mm S2: Ø6.68 mm
A397		X	X	X		11.00 mm	0.30	7.20 mm	9.64 mm^a	8.44 mm^a,c	Ø6.59 mm
354560	X	X	X	X		13.86 mm	0.2	6.325 mm	12.1 mm^a	11.7 mm^a,c	S1: Ø4.54 mm S2: Ø5.10 mm
A260		X	X	X		15.29 mm	0.16	6.50 mm	14.09 mm^a	13.84 mm^a,c	Ø5.00 mm
354260	X	X	X	X		15.3 mm	0.2	6.500 mm	12.7 mm^b	12.4 mm^b,c	S1: Ø4.61 mm S2: Ø5.00 mm
A280		X	X	X		18.40 mm	0.15	6.50 mm	17.13 mm^a	16.88 mm^a,c	Ø5.50 mm
354280	X	X	X	X	1064	18.4 mm	0.15	6.500 mm	15.9 mm^b	15.6 mm^b,c	S1: Ø5.15 mm S2: Ø5.50 mm

This working distance is measured to the focal point.
This working distance is measured to the front of the window of the laser diode being collimated.
Measured from the Mount

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EFL = 0.x mm

Item # (Unmounted)	Info	EFL^a	NA	OD	WD^b	CA	T_C	DW	LWT^c	Glass	Performance
355465		0.5 mm	S1: 0.50 S2: 0.10	1.845 mm	S1: 0.3 mm^dS2: 2.9 mm^d	S1: Ø0.40 mm S2: Ø0.70 mm	0.782 mm	1310 nm	-	D-ZLaF52LA	Focal Shift / Spot Size Cross Section
355915		0.8 mm	S1: 0.50 S2: 0.12	1.300 mm	S1: 0.7 mm^d S2: 3.9 mm^d	S1: Ø0.77 mm S2: Ø1.00 mm	0.600 mm	1550 nm	-	D-ZLaF52LA	Focal Shift / Spot Size Cross Section

EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured to the focal point.

EFL = Effective Focal Length
NA = Numerical Aperture
CA = Clear Aperture

WD = Working Distance
DW = Design Wavelength
T_C = Center Thickness

OD = Outer Diameter
LWT = Laser Window Thickness

EFL = 1.x mm

Item # (Unmounted)	EFL^a	NA	OD	WD^b	CA	T_C	DW	LWT^c	Glass	Performance
355200	1.1 mm	S1: 0.43 S2: 0.12	2.400 mm	S1: 0.5 mm^d S2: 4.8 mm^e	S1: Ø1.24 mm S2: Ø1.24 mm	1.239 mm	1300 nm	0.300 mm	D-ZLaF52LA	Focal Shift / Spot Size Cross Section
355201^f	1.1 mm	S1: 0.12 S2: 0.43	4.929 mm	S1: 0.5 mm^d S2: 4.8 mm^e	S1: Ø1.24 mm S2: Ø1.24 mm	1.239 mm	1300 nm	0.305 mm	D-ZLaF52LA	Focal Shift / Spot Size Cross Section
354450	1.2 mm	S1: 0.30 S2: 0.30	1.800 mm	S1: 1.7 mm^e S2: 1.7 mm^e	S1: Ø1.14 mm S2: Ø1.14 mm	1.480 mm	980 nm	-	D-ZK3	Focal Shift / Spot Size Cross Section
355755	1.9 mm	S1: 0.15 S2: 0.15	1.700 mm	S1: 3.6 mm^e S2: 3.6 mm^e	S1: Ø1.10 mm S2: Ø1.10 mm	1.000 mm	1577 nm	-	D-ZLaF52LA	Focal Shift / Spot Size Cross Section

EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured to the front of the window of the laser diode being collimated.
This working distance is measured to the focal point.
This lens is housed in a metal ring.

EFL = Effective Focal Length
NA = Numerical Aperture
CA = Clear Aperture

WD = Working Distance
DW = Design Wavelength
T_C = Center Thickness

OD = Outer Diameter
LWT = Laser Window Thickness

EFL = 2.8 mm

Item # (Unmounted/ Mounted)	Info	EFL^a	NA	OD	WD^b	CA	T_C	DW	LWT^c	Glass	Performance	Thread	Suggested Spanner Wrench
355440		2.8 mm	S1: 0.26 S2: 0.52	4.700 mm	S1: 2.0 mm^d S2: 7.1 mm^e	S1: Ø3.76 mm S2: Ø4.12 mm	3.827 mm	980 nm	0.250 mm	D-ZLaF52LA	Focal Shift / Spot Size Cross Section	-	-
C440TMD		2.8 mm	S1: 0.26 S2: 0.52	8.2 mm	S1: 1.9 mm^d,f	S1: Ø3.76 mm S2: Ø4.12 mm	3.827 mm	980 nm	0.250 mm	D-ZLaF52LA		M8 x 0.5	SPW308

EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured to the front of the window of the laser diode being focused.
This working distance is measured to the focal point.
Measured from the Mount

EFL = Effective Focal Length
NA = Numerical Aperture
CA = Clear Aperture

WD = Working Distance
DW = Design Wavelength
T_C = Center Thickness

OD = Outer Diameter
LWT = Laser Window Thickness