Thorlabs N-BK7 A-Coated Bi-Convex Lens LB1889-A — New Sealed
f = 250 mm on a 2 inch aperture, sealed and unused
Longer focal lengths focus more gently, which means a larger spot and a longer depth over which that spot stays usable. When a beam has to cross a sample chamber or an alignment needs tolerance rather than tightness, 250 mm gives more of both than a short lens can.
Paired with a shorter element it also makes a straightforward beam expander: a 50 mm and this lens give five times expansion. N-BK7 substrate, A antireflection coating covering roughly 350 to 700 nm.
Where it earns its place
- Beam expanders where a defined ratio is needed
- Gentle focusing across a sample chamber or long path
- Alignment-tolerant setups where depth of focus matters
- Stock glass for a bench that reconfigures often
Specifications
| Brand | Thorlabs |
|---|---|
| MPN | LB1889-A |
| Lens type | Bi-convex |
| Diameter | 50.8 mm |
| Focal length | 250.0 mm |
| Substrate | N-BK7 |
| Coating | A, antireflection |
| Condition class | New, sealed |
Condition
New and unused in the original packaging. Photographs show the exact item you receive.
Understanding Item Conditions
- New: Unused equipment.
- Used: Previously owned equipment, tested for functionality.
- Refurbished: Previously owned equipment that has undergone restoration or servicing.
Thorlabs N-BK7 A-Coated Bi-Convex Lens LB1889-A — New Sealed is backordered and will ship as soon as it is back in stock.
For universities & labs: formal quotes and purchase orders
Pickup available at 1128 Western St
Usually ready in 24 hours
Shipping and Delivery
Shipping and Delivery
Shipping Costs
- Customers are responsible for all shipping costs associated with their order.
- Shipping fees will be calculated at checkout based on the weight, dimensions, and destination of your package.
- Any applicable taxes, duties, or customs fees for international orders are also the responsibility of the customer.
Processing Time
- Orders are processed within 2 business days after payment has been received.
- We do not process or ship orders on weekends or holidays.
Shipping Methods
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- Available shipping options will be displayed at checkout. Customers can select the method that best suits their needs.
Delivery Times
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Tracking Your Order
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Lost, Damaged, or Delayed Shipments
- We are not responsible for lost or delayed shipments caused by the carrier.
- If your package arrives damaged, please contact us within within 48 hours with photos of the damage, and we will assist in filing a claim with the carrier.
Returns Due to Incorrect Address
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- Orders returned to us due to incorrect or incomplete addresses will require additional shipping fees for reshipment.
Questions?
If you have any further questions about our shipping policy, feel free to reach out to us at info@misterscientific.com. We're here to help!
Thorlabs N-BK7 A-Coated Bi-Convex Lens LB1889-A — New Sealed
Thorlabs N-BK7 A-Coated Bi-Convex Lens LB1889-A — New Sealed is backordered and will ship as soon as it is back in stock.
Request a quote
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