send sns topic alert when a specific file is uploaded to s3

Question

I want to create a cloudwatch event which will send a sns topic alert when a file starting with SampleSheet is uploaded to a s3 bucket.

below configuration creates alert for every object uploaded to s3:

 {
          "source": [
            "aws.s3"
          ],
          "detail": {
            "eventSource": [
              "s3.amazonaws.com"
            ],
            "eventName": [
              "PutObject"
            ],

            "requestParameters": {
              "bucketName": [
                "Mys3bucktet"
              ]
            }
          }
        }

I want to create an alert only when file 'samplesheet.csv' is uploaded to s3 bucktet and i tried something like below which is not working:

      {
          "source": [
            "aws.s3"
          ],
          "detail": {
            "eventSource": [
              "s3.amazonaws.com"
            ],
            "eventName": [
              "PutObject"
            ],
            "Prefix": [
              "SampleSheet"
            ],
            "requestParameters": {
              "bucketName": [
                "Mys3bucktet"
              ]
            }
          }
        }