如何在PHP中通过AWS SNS发送短信中的utf-8字符？

我有以下简单的代码来根据传入的api请求发送SMS消息，但是消息到达手机时，重音被相应的ascii版本替换

我应该做些什么改变才能让“你赢得了亚欧产品”这样的信息正确到达

<?php
use Illuminate\Http\Request;
use Illuminate\Routing\Controller as BaseController;
use Aws\Sns\SnsClient;
use Aws\Credentials\Credentials;

class Controller extends BaseController
{
  public function send(Request $request){    
    $to = $request->input('phone');
    $message = $request->input('message');

    $client = new SnsClient([
      'version' => '2010-03-31',
      'credentials' => new Credentials(
          env('SMS_AWS_ACCESS_KEY_ID'),
          env('SMS_AWS_SECRET_ACCESS_KEY')
      ),
      'region' => env('SMS_AWS_DEFAULT_REGION'),
    ]);

    $client->SetSMSAttributes([
      'attributes' => [
          'DefaultSMSType' => 'Transactional',
      ]
    ]);

    $client->publish([
      'Message' => $message,
      'PhoneNumber' => $to,
    ]);

    return [$to, $message];
  }
}