Company: LASR
Filing Date: 2025-04-25
Form Type: DEFA14A
Source: 0001124796-25-000044
Chunk: 0

Company: NLIGHT, INC.
Filing Date: 2025-04-25
Form: DEFA14A
Chunk 0
---
### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington, D.C. 20549

#### SCHEDULE 14A

#### PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE

#### SECURITIES EXCHANGE ACT OF 1934
Filed by the Registrant ý

Filed by a party other than the Registrant ¨

Check the appropriate box:

¨ Preliminary Proxy Statement

¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a‑6(e)(2))

¨ Definitive Proxy Statement

ý Definitive Additional Materials

¨ Soliciting Material under §240.14a‑12

#### NLIGHT, INC.
<div align='center'>(Name of Registrant as Specified In Its Charter)</div>

<div align='center'>(Name of Person(s) Filing Proxy Statement, if other than the Registrant)</div>

| Payment of Filing Fee (Check all boxes that apply): |     |                                                                                                     |
| ý                                                   |     | No fee required                                                                                     |
| ¨                                                   |     | Fee paid previously with preliminary materials                                                      |
| ¨                                                   |     | Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11 |