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    Visa Information and Invitation Requests

    Apply now for your Visa

    Because of the number of visa applications and the need for thorough security reviews, the visa application process can take several months. It is strongly encouraged travelers to apply for their visas as early as possible (at least 3 to 4 months before the visa is needed).

    SPIE is aware that China is in the process of reissuing new biometric passports. We will do our best to accommodate our authors with revisions of invitation letters, as needed. Any revised letters will be sent via email and First Class Postal Mail.

    Passport Requirements to Enter the United States

    • As of 31 December 2006, anyone traveling to or from the US via air or sea from Canada, Mexico, Central and South America, the Caribbean, and Bermuda must have a passport or other secure, accepted document to enter or re-enter the US.
    • As of 1 June 2009, the above requirement extends to all land border crossings, as well as air and sea travel.
    • You must have a passport that is valid for at least 6 months after your planned departure from the United States (unless exempted by country-specific agreements).

    Online Resources

    U.S. State Dept. Visa Information:
    Department of Homeland Security:
    U.S. Customs and Border Information:
    International Visitors Office:

    Visa Waiver Program (VWP) and Electronic System for Travel Authorization (ESTA) FAQs
    As of 1 April 2016, visitors to the U.S. from visa-waiver countries, most of which are in Europe, will be required to have an e-Passport, register online and to be screened and authorized for entry through the Electronic System for Travel Authorization (ESTA) program.

    Electronic Visa Update System (EVUS) FAQs
    As of 29 November 2016, new electronic registration requirements are in effect for Chinese citizens.

    How to Request an Invitation Letter

    • You must be in the technical program or an exhibitor to receive an invitation letter. Select and complete the appropriate form, and return to SPIE via

    • Please fill out a separate invitation letter request form for each person requesting a letter.
    • Your name must be listed exactly as it appears on your 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.
    • All letters of invitation will be sent by email (as a PDF attachment), and 1st Class postal mail by request.
    • Expect up to 3 weeks to receive the PDF copy of your invitation letter by email, and additional time to receive the original letter by post.
    • SPIE is unable to contact U.S. Embassies in support of an individual attempting to gain entry to attend an SPIE meeting.
    • We recommend that you secure your travel visa before registering for the conference as cancellations after the preregistration cutoff may result in a cancellation fee.

    Visa Guidelines

    Visa Background Information

    Because of the number of visa applications and the need for thorough security reviews, the visa application process can take several months. It is strongly encouraged travelers to apply for their visas as early as possible (at least 3 to 4 months before the visa is needed).

    Contact the nearest U.S. consulate or embassy for details on visa application procedures.

    Guidelines for Successful Visa Applications:

    • Visa applicants are expected to provide evidence that they are intending to return to their country of residence. This may include documentation of the following:
      • family ties in home country or country of legal permanent residence
      • property ownership
      • bank accounts
      • employment contract or statement from employer stating that the position will continue when the employee returns
    • Visa applications are more likely to be successful if completed in a visitor's home country than in another country
    • Applicants should present their entire trip itinerary, including travel to any countries other than the United States, at the time of their visa application
    • Include a letter of invitation from the meeting organizer or the U.S. host, specifying the subject, location and dates of the activity, and how travel and local expenses will be covered
    • If travel plans will depend on early approval of the visa application, specify this at the time of the application
    • Provide proof of professional scientific and/or educational status (students should provide a university transcript)
    • Any evidence that establishes a prior record of business travel to exhibitions and other events is helpful. A photograph of an applicant staffing an exhibit booth, receipts for admission, purchases of goods and services to support an exhibit booth at an event, are all potentially valuable evidence that may tip the balance in favor of visa approval.

    Information to Take to the Interview:

    • Evidence of prior related business travel, even travel to countries other than the United States (US).
    • A business resume written in English.
    • A letter of invitation containing anti-counterfeit measures from the sponsoring organization, such as SPIE, as well as personal information about the applicant such as a passport number, Paper Number, etc.

    Even those who have traveled frequently to the US for business purposes might encounter difficulties from time to time that might have little to do with their standing as individuals. The nature of the products and/or industry in which they have become involved such as certain types of US controlled goods (wireless technology, electronics, and such) may give rise to difficulties and/or delays. The political climate and current state of relations between the nations may become a factor. In other words, a prior history of travel to the US is never a guarantee of future admission.

    Visa Difficulties

    SPIE does not have any influence with the State Department or the Office of Homeland Security. If your visa is delayed (60 days or longer) or denied, please contact the consulate where your application is being processed. Also, please contact the National Academies' International Visitors Office and fill out the questionnaire:

    The International Visitors office regularly reports to the State Department (submitted through the Visa Questionnaire) about applications which have been pending for longer than 60 days.