Does Salesforce SOSL works after enabling probabilistic encryption is enabled on the search field ?
No, it won't work because each bit of data is turned into a fully random ciphertext string every time it’s encrypted.
Also from Salesforce docs:
By default, Salesforce encrypts data using a probabilistic encryption scheme. Each bit of data is turned into a fully random ciphertext string every time it’s encrypted. Encryption doesn’t generally impact users who are authorized to view the data. The exceptions are when logic is executed in the database or when encrypted values are compared to a string or to each other. In these cases, because the data has been turned into random, patternless strings, filtering isn’t possible. For example, you might run a SOQL query in custom Apex code against the Contact object, where LastName = 'Smith'. If the LastName field is encrypted with probabilistic encryption, you can’t run the query.
For this we need Deterministic Encryption. How Deterministic Encryption Supports Filtering