Passport requirements to enter the United States
- 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
- 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)
US State Dept. Visa Information
US Department of Homeland Security
US Customs and Border Information
International Visitors Office
Visa Waiver Program (VWP) and Electronic System for Travel Authorization (ESTA) FAQs
Visitors to the US from visa-waiver countries, most of which are in Europe, are required to have an e-Passport, register online, and 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 - for authors and attendees only
- Sign in to this site using your SPIE credentials (username and password)
- After you are signed in, click on this link to go directly to the SPIE invitation letter request form page
- Click on the “Apply” button to begin the invitation letter request form.
- Complete one form per person (requests for accompanying family members can be included in the same application)
- Your name must be listed exactly as it appears on your passport. Any differences could lead to delay or denial of your visa
- Requests are processed based on the order received, and the date of the conference
- You will receive an email from "email@example.com" with a link to download a PDF of your official invitation letter after it is approved and processed. You should also make sure that the sites listed here, are allowed by your organization to ensure you receive the email.
- Printed invitation letters are mailed by request only. Please allow up to four weeks for delivery
- SPIE is unable to contact embassies or consulates on behalf of or in support of any individual making arrangements to attend an SPIE event
- If you have questions regarding invitation letters or changes are needed to an existing invitation letter, contact firstname.lastname@example.org (include your SPIE Paper Number)
How to request an invitation letter - for exhibitors only
To request an invitation letter, if you are an exhibitor at an SPIE event, fill out and submit the Exhibitor Invitation Letter Request Form
- For exhibitors requiring a letter of invitation from SPIE to obtain a travel visa to participate in the exhibition
- You must be listed as an exhibitor (or co-exhibitor) of this exhibition or your request will not be processed
- Requests are processed and prioritized based on the order received and the date of the exhibition (usually within 3 weeks)
- The invitation letter PDF will be sent via OneDrive with a link to access the Invitation Letter, and by FEDEX if requested
- SPIE is unable to contact embassies or consulates in support of an individual attempting to attend an SPIE exhibition
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. SPIE strongly encourages travelers to apply for their visas as early as possible (at least three to four months before the visa is needed).
Contact the nearest US 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 US 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
- 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.
SPIE does not have any influence with the US Department of State 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 that have been pending for longer than 60 days.