Letter of Invitation

Letters of Invitation (or Visa Letters) now require the requestor to register first. After registering, a confirmation email with a link to the Letter of Invitation Request Form will be sent. Once the form is complete and submitted, an email with a link to download a PDF Letter of Invitation will be sent. Please note: Letters of Invitation are non-transferable. Show Management will not edit or update a completed Letter of Invitation. 

Important information regarding Visa Invitation Letters:

• The name of the registrant must be an exact match as it appears on their passport. Any differences between the name on your passport and the name on your invitation letter or other documentation could lead to a delay and/or denial of your visa. 
• If you are presenting a paper, include the title and session in which the paper will be presented, or if you are exhibiting, please indicate so in your request.
• Please note that each individual requesting an invitation letter must fill out a separate form. All letters will be sent in PDF form to the email address provided. 

If you are not a U.S. citizen and plan to attend the Optica Advanced Photonics Congress in person, advance planning is crucial.

Citizens of some foreign countries will need a visa to enter the United States and attend the Advanced Photonics Congress. Due to U.S. State Department regulations, U.S. embassies and consulates typically require a face-to-face interview for most non-immigrant visa applications.

Schedule Your Interview

There is no required documentation to schedule your face-to-face visa interview; you do not need to be registered, have a hotel reservation, or have a travel itinerary to make an appointment. Optica strongly suggests that all international travelers schedule face-to-face interviews as soon as possible.

Please note: While travelers should schedule their appointment as soon as possible, the appointment itself should take place after registering for the Advanced Photonics Congress. Visa letters for the congress will become available once registration opens. Registration for the Advanced Photonics opens in late March 2026.

To schedule an interview for the visa application process, please contact the nearest U.S. embassy or consulate. For more information, please visit travel.state.gov/content/visas/en.html.

For current visa wait times, please visit https://travel.state.gov/content/travel/en/us-visas/visa-information-resources/global-visa-wait-times.html.

For questions about the visa invitation letter application process, send an email to invitations@optica.org

Visa Information 

If you need a travel visa, begin the visa application process now. The application process can take up to six (6) months or more. We strongly encourage you to apply for your visa as early as possible, but no later than three months before you wish to enter the United States. Strict security requirements may cause delays in visa processing.

Learn more about the visa application process. >

Resources

• U.S. Customs and Border Information
• VWP and ESTA: Frequently Asked Questions
• U.S. State Department Visa Information
• Department of Homeland Security
• National Academies International Visitors Office

ESTA Application

ESTA is an automated system that determines the eligibility of visitors to travel to the United States under the Visa Waiver Program (VWP). Authorization via ESTA does not determine whether a traveler is admissible to the United States. U.S. Customs and Border Protection officers determine admissibility upon a traveler's arrival. The ESTA application collects biographic information and answers to VWP eligibility questions. ESTA applications may be submitted at any time prior to travel, though it is recommended that travelers apply as soon as they begin preparing travel plans or prior to purchasing airline tickets.

Learn more about an ESTA application. >